Process for preparing a detergent tablet

ABSTRACT

A process for preparing a multi-phase detergent tablet comprising the steps of: 
     a) forming a tablet body by compressing a granular detergent mixture, said tablet body having a first surface, said first surface having at least one mold therein and said granular detergent mixture comprises at least one detergent active agent; 
     b) providing a gelatinous mixture under constant agitation, and delivering said gelatinous mixture to said at least one mold in said tablet body to form a gelatinous portion, said gelatinous mixture comprises at least one detergent active agent; and 
     c) hardening or curing said gelatinous portion to form a multi-phase detergent tablet.

This application is a 371 of PCT/US98/23616 filed Nov. 5,1998 whichclaims the benefit of U.S. Provisional Application No. 60/065,035 filedNov. 10, 1997 and U.S. Provisional Application No. 60/072,479 filed Jan.26, 1998.

TECHNICAL FIELD

The present invention relates to a process for the preparation ofdetergent tablets having multiple-layers and, more particularly, todetergent tablets having both compressed and gelatinous portions.

BACKGROUND OF THE INVENTION

Detergent compositions in tablet form are known in the art. Detergentcompositions in tablet form hold several advantages over detergentcompositions in particulate or liquid form, such as case of use andhandling, convenient dosing, ease of transportation and storage. Due tothese advantages, detergent compositions in tablet form are becomingincreasingly popular with consumers of detergent products.

Detergent tablets are most commonly prepared by pre-mixing thecomponents and forming the pre-mixed components into a tablet via theuse of a tablet press and compression of the components. However,traditional tablet compression processes have significant drawbacks,including but not limited to the fact that selected components of adetergent composition may be adversely affected by the compressionpressure in the tablet press. Accordingly, these selected componentswere not typically included in prior art detergent tablets withoutsustaining a loss in performance. In some cases, these selectedcomponents may even have become unstable or inactive as a result of thecompression.

In addition, as the components of the detergent composition arecompressed in the tablet press, they are brought into close proximitywith one another resulting in the reaction of selected components,instability, inactivity or exhaustion of the active form of thecomponents.

To avoid the above mentioned drawbacks, prior art detergent tablets haveattempted to separate components of the detergent composition that maypotentially react with each other when the detergent composition iscompressed into tablet form. Separation of the components has beenachieved by, for example, preparing multiple-layer tablets wherein thereactive components are contained in different layers of the tablet orencapsulation and coating of reactive components. These prior artmultiple-layer tablets are traditionally prepared using multiplecompression steps. Accordingly, layers of the tablet which are subjectedto more than one compression step may be subjected to a cumulative andpotentially greater overall compression pressure. In addition, anincrease in compression pressure of the tabletting press is known todecrease the rate of dissolution of the tablet with the effect that suchmultiple layer tablets may not dissolve satisfactorily in use. Nor isthere any significant variation in the dissolution rates of the multiplelayers.

Accordingly, the need remains for an improved detergent tablet which candeliver active detergent ingredients to a domestic wash process therebydelivering superior performance benefits.

SUMMARY OF THE INVENTION

This need is met by the present invention wherein a process for thepreparation of a detergent tablet having a tablet body and a gelatinousportion is provided. The process of the present invention provides adetergent tablet having a superior delivery mechanism for detergentcomponents in addition to effectively separating potentially reactiveingredients. A detergent tablet prepared by the process of the presentinvention is also provided for. The detergent tablet produced providessuperior cleaning performance, particularly in domestic automaticdishwashing machines over the tablets of the prior art.

According to a first embodiment of the present invention, a process forpreparing a multi-phase detergent tablet is provided for comprising thesteps of:

a) forming a tablet body by compressing a granular detergent mixture,said tablet body having a first surface, said first surface having atleast one mold therein and said granular detergent mixture comprises atleast one detergent active agent;

b) providing a gelatinous mixture under constant agitation, anddelivering said gelatinous mixture to said at least one mold in saidtablet body to form a gelatinous portion, said gelatinous mixturecomprises at least one detergent active agent; and

c) hardening or curing said gelatinous portion to form a multi-phasedetergent tablet.

Preferably, the gelatinous portion is formulated so that at least 80% ofthe detergent active is delivered to the wash within the first 5 minutesof a domestic wash process, and more preferably at least 90% of thedetergent active is delivered to the wash within the first 3 minutes ofa domestic wash process. The detergent active agent in the gelatinousportion may be selected from the group consisting of enzymes,surfactants, drying agents, alkalinity source, disrupting agents,bleaching agents, silver care agents, builders, and mixtures thereofwith enzymes and disrupting agents being the most preferred. When adisrupting agent is included, the disrupting agent is preferably a saltof carbonate or bicarbonate and an organic acid.

In alternative preferred embodiments, the gelatinous portion contains atleast about 15% suspended solids and more preferably at least about 40%of the gelatinous portion is a suspended solid. The gel portion mayfurther include a swelling/adsorbing agent.

The thickening system of the present invention preferably comprises amixture of a non-aqueous diluent or solvent and a gelling agent. Thegelling agent may be selected from the group consisting of castor oilderivatives, polyethylene glycol and mixtures thereof and is preferablypolyethylene glycol. The non-aqueous diluent may be selected from thegroup consisting of low molecular weight polyethylene glycols, glyceroland modified glycerols, propylene glycol, alkyleneglycol alkyl ethersand mixtures thereof and is preferably dipropyleneglycol butylether,propylene glycol or glycerol triacetate.

Lastly, the weight ratio of the tablet body to the non-compressedgelatinous portion is preferably greater than about 0.5:1 and the tabletbody of the detergent tablet preferably has a dissolution rate ofgreater than 0.33 g/min as determined using the SOTAX dissolution testmethod.

Accordingly, it is an aspect of the present invention to provide aprocess for preparing a detergent tablet having a tablet body which isformed by compression of a granular detergent mixture. The tablet bodyhaving a first surface, and the first surface having at least one moldtherein. A gelatinous mixture is then formed and added to the at leastone mold forming a gelatinous portion therein. Hardening or curing thegelatinous portion to form a multi-phase detergent tablet. It is afurther aspect of the present invention to produce a detergent tabletcontaining a gelatinous portion which can quickly and efficientlydeliver detergent actives to a domestic wash process. It is stillfurther an aspect of the present invention to provide a process ofpreparing a detergent tablet having a gelatinous portion which is apumpable, flowable solid in liquid mixture or suspension, at slightlyelevated temperature yet thickens or hardens to maintain its form atambient temperatures, particularly when shear is removed from thegelatinous mixture. These, and other aspects, features and advantages ofthe present invention will be readily apparent to one of ordinary skillin the art from the following detailed description and the appendedclaims.

All percentages, ratios and proportions herein are by weight, unlessotherwise specified. All temperatures are in degrees Celsius (° C.)unless otherwise specified. All documents cited are in relevant part,incorporated herein by reference.

Definition

The term “gelatinous mixture” as used herein means that the mixtureupon, cooling, being cooled, hardening, removing from agitation, orcuring becomes gelatinous. That is, it forms the gelatinous portionwhich is gelatinous. The gelatinous mixture can be any possible type ofmixture provided that on cooling, hardening, removing from agitation orcuring, it becomes gelatinous. For example, the gelatinous mixture couldbe a liquid, a solid in liquid mixture/suspension or even a gel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention comprises a process for preparing a detergenttablet and in particular a detergent tablet for automatic dishwashinghaving a tablet body which is formed by compression of a granulardetergent mixture. The tablet body having a first surface, has at leastone mold therein and comprises at least one detergent active agent. Agelatinous mixture, under constant agitation, is then formed and addedto the at least one mold forming a gelatinous portion therein. Thegelatinous mixture comprises at least one detergent active agent. Thegelatinous portion is then cured or hardened or cured to form amulti-phase detergent tablet. The use of the gelatinous portion providesa superior delivery mechanism for detergent active agents into thedomestic wash process. The gelatinous portion provides unique propertiesof rapid dissolution or dispersion thereby providing for the earliestpossible delivery of detergent active agents into the domestic washprocess.

Accordingly, by way of the present invention, detergent active agents ofa detergent tablet previously adversely affected by the compressionpressure used to form the tablets may now be included in a detergenttablet. Examples of these agents include bleaching agents and enzymes.Furthermore, enzymes in the form of prills can now be included intodetergent tablets without the prill being destroyed or damaged duringthe production of the detergent tablet. In addition, these activedetergent components may be separated from one another by having one ormore compatible components contained in the tablet body and one or morecompatible components contained in the gelatinous portion of the tablet.Examples of components that may interact and may therefore requireseparation include bleaching agents, bleach activators or catalyst andenzymes; bleaching agents and bleach catalysts or activators; bleachingagents and surfactants; alkalinity sources, perfumes and enzymes.

It may be advantageous to provide the tablet body and the gelatinousportions such that they dissolve in the wash water with differentdissolution rates. By controlling the rate of dissolution of eachportion relative to one another, and by selection of the activedetergent components in the respective portions, their order of releaseinto the wash water can be controlled and the cleaning performance ofthe detergent tablet may be improved. For example it is often preferredthat enzymes are delivered to the wash prior to builders and/orbleaching agent and/or bleach activator. It may also be preferred that asource of alkalinity is released into the wash water more rapidly thanother components of the detergent tablet. It is also envisaged that itmay be advantageous to prepare a detergent tablet according to thepresent invention wherein the release of certain components of thetablet is delayed relative to other components.

The tablet may also comprise a plurality of compressed ornon-compressed, gelatinous portions. For example, a plurality ofcompressed portions may be arranged in layers and/or a plurality ofnon-compressed portions may be present as discrete sections of thetablet separated by a compressed portion. Thus, there may be a first anda second and optional subsequent compressed and/or non-compressed,gelatinous portions, each comprising an active detergent component andwhere at least the first and second portions may comprise differentactive detergent components or mixtures of components. Such a pluralityof compressed or non-compressed, gelatinous portions may beadvantageous, enabling a tablet to be produced which has for example, afirst and second and optional subsequent portions so that they havedifferent rates of dissolution. Such performance benefits are achievedby selectively delivering active detergent components into the washwater at different times.

The tablet body of the detergent tablets described herein are preferablybetween 15 g and 100 g in weight, more preferably between 18 g and 80 gin weight, even more preferably between 20 g and 60 g in weight. Thedetergent tablet described herein that are suitable for use in automaticdishwashing methods are most preferably between 20 g and 40 g in weight.Detergent tablets suitable for use in fabric laundering methods are mostpreferably between 40 g and 100 g, more preferably between 40 g and 80g, most preferably between 40 g and 65 g in weight. The weight ratio oftablet body to gelatinous portion is generally greater than 0.5:1,preferably greater than 1:1, more preferably greater than 2:1, even morepreferably greater than 3:1 or even 4:1, most preferably at least 5:1.

The tablet body of the detergent tablets described herein have ChildBite Strength (CBS) which is generally greater than 10 Kg, preferablygreater than 12 Kg, most preferably greater than 14 Kg. CBS is measuredas per the U.S. Consumer Product Safety Commission Test Specification.

Child Bite Strength Test Method: According to this method the tablet isplaced horizontally between two strips/plates of metal. The upper andlower plates are hinged on one side, such that the plates resemble ahuman jaw. An increasing downward force is applied to the upper plate,mimicking the closing action of the jaw, until the tablet breaks. TheCBS of the tablet is a measure of the force in Kilograms, required tobreak the tablet.

The tablet body of the detergent tablets described herein generally havea dissolution rate of faster than 0.33 g/min, preferably faster than 0.5g/min, more preferably faster than 1.00 g/min, even more preferablyfaster than 2.00 g/m, most preferably faster than 2.73 g/min.Dissolution rate is measured using the SOTAX dissolution test method.For the purposes of the present invention dissolution of detergenttablets is achieved using a SOTAX (tradename) machine; model number AT7available from SOTAX.

SOTAX Dissolution Test Method: The SOTAX machine consists of atemperature controlled waterbath with lid. 7 pots are suspended in thewater bath. 7 electric stirring rods are suspended from the underside ofthe lid, in positions corresponding to the position of the pots in thewaterbath. The lid of the waterbath also serves as a lid on the pots.

The SOTAX waterbath is filled with water and the temperature gauge setto 50° C. Each pot is then filled with 1 liter of deionised water andthe stirrer set to revolve at 250 rpm. The lid of the waterbath isclosed, allowing the temperature of the deionised water in the pots toequilibrate with the water in the waterbath for 1 hour.

The tablets are weighed and one tablet is placed in each pot, the lid isthen closed. The tablet is visually monitored until it completelydissolves. The time is noted when the tablet has completely dissolved.The dissolution rate of the tablet is calculated as the average weight(g) of tablet dissolved in deionised water per minute.

Tablet Body

The tablet body of the detergent tablet comprises at least one activedetergent component but may comprise a mixture of more than one activedetergent components, which are compressed. Any detergent tabletcomponent conventionally used in known detergent tablets is suitable forincorporation into the compressed portion of the detergent tablets ofthis invention. Suitable active detergent components are describedhereinafter. Preferred active detergent components include buildercompound, surfactant, bleaching agent, bleach activator, bleachcatalyst, enzyme and an alkalinity source.

Active detergent component(s) present in the tablet body may optionallybe prepared in combination with a carrier and/or a binder for examplewater, polymer (e.g. PEG), liquid silicate. The active detergentcomponents are preferably prepared in particulate form (i.e. powder, orgranular form) and may be prepared by any known method, for exampleconventional spray drying, granulation or agglomeration. The particulateactive detergent component(s) are then compressed using any suitableequipment suitable for forming compressed tablets, blocks, bricks orbriquettes; described in more detail hereafter.

The tablet body has a first surface in which there is at least one mold.This mold acts as a reservoir for the gelatinous portion duringmanufacture of the detergent tablet.

The tablet body may also be provided with a coating of a water-solublematerial to protect the tablet body. The coating layer preferablycomprises a material that becomes solid on contacting the tablet bodyand/or the gelatinous portions within preferably less than 15 minutes,more preferably less than 10 minutes, even more preferably less than 5minutes, most preferably less than 60 seconds. Preferably the coatinglayer is water-soluble. Preferred coating layers comprise materialsselected from the group consisting of fatty acids, alcohols, diols,esters and ethers, adipic acid, carboxylic acid, dicarboxylic acid,polyvinyl acetate (PVA), polyvinyl pyrrolidone (PVP), polyacetic acid(PLA), polyethylene glycol (PEG) and mixtures thereof. Preferredcarboxylic or dicarboxylic acids preferably comprise an even number ofcarbon atoms. Preferably carboxylic or dicarboxylic acids comprise atleast 4, more preferably at least 6, even more preferably at least 8carbon atoms, most preferably between 8 and 13 carbon atoms. Preferreddicarboxylic acids include adipic acid, suberic acid, azelaic acid,subacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic andmixtures thereof. Preferred fatty acids are those having a carbon chainlength of from C12 to C22, most preferably from C18 to C22. The coatinglayer may also preferably comprise a disrupting agent. Where present thecoating layer generally present at a level of at least 0.05%, preferablyat least 0.1%, more preferably at least 1%, most preferably at least 2%or even at least 5% of the detergent tablet.

Gelatinous-Portion

As noted earlier, a gelatinous portion is mounted or formed into the atleast one mold in the first surface of the tablet body of the detergenttablet. The gelatinous portion comprises a thickening system and atleast one detergent active agent. The gelatinous-portion is preferablyformulated such that the detergent active ingredient is essentiallycompletely delivered in a short period of time. Typically, thegelatinous portion is formulated so that at least about 80% of thedetergent active is delivered to the wash of a domestic washing processwithin the first 5 minutes, more preferably at least about 90% in thefirst 3 minutes and even more preferably 95% within the first 2 minutesas measured from the first point at which the tablet including thegelatinous portion is completely immersed in water, particularly in coldwater temperatures, such as, e.g., 250° C. Thus, the tablet of thepresent invention is particularly effective at delivering detergentactives in varying water temperatures including cold water.

The gelatinous portion may include solid ingredients which are dispersedor suspended within the gel. Examples of these solid ingredientsinclude, any detergent active agents, for example disruption system,drying agents, alkaline material. The solid ingredients aid in thecontrol of the viscosity of the gelatinous mixture in conjunction withthe thickening system. In addition, solid ingredients may act tooptionally disrupt the gel thereby aiding in dissolution of thegelatinous portion. When included, the gelatinous portion typicallycomprises at least about 15% solid ingredients, more preferably at leastabout 30% solid ingredients and most preferably at least about 40% solidingredients. However, due to pumpability and other processing concerns,the gelatinous portions of the present invention typically do notinclude more than about 90% solid ingredients.

Thickening System

As noted earlier, the detergent tablet of the present inventioncomprises a thickening system in the gelatinous mixture to provide theproper viscosity or thickness of the gelatinous portion. The thickeningsystem typically comprises a non-aqueous liquid diluent and an organicor polymeric gelling additive

a) Liquid Diluent

The term “solvent” or “diluent” is used herein to connote the liquidportion of the thickening system. While some of the essential and/oroptional components of the compositions herein may actually dissolve inthe “solvent” -containing phase, other components will be present asparticulate material dispersed within the “solvent” -containing phase.Thus the term “solvent” is not meant to require that the solventmaterial be capable of actually dissolving all of the detergentcomposition components added thereto. Suitable types of solvents usefulin the non-aqueous thickening systems herein include alkylene glycolmono lower alkyl ethers, propylene glycols, ethoxylated or propoxylatedethylene or propylene, glycerol esters, glycerol triacetate, lowermolecular weight polyethylene glycols, lower molecular weight methylesters and amides, and the like and mixtures thereof, with glyceroltriacetate being preferred.

A preferred type of non-aqueous solvent for use herein comprises themono-, di-, tri-, or tetra- C₂-C₃ alkylene glycol mono C₂-C₆ alkylethers. The specific examples of such compounds include diethyleneglycol monobutyl ether, tetraethylene glycol monobutyl ether,dipropylene glycol monoethyl ether, and dipropylene glycol monobutylether. Diethylene glycol monobutyl ether and dipropylene glycolmonobutyl ether are especially preferred. Compounds of the type havebeen commercially marketed under the tradenames Dowanol, Carbitol, andCellosolve.

Another preferred type of non-aqueous solvent useful herein comprisesthe lower molecular weight polyethylene glycols (PEGs). Such materialsare those having molecular weights of at least about 150. PEGs ofmolecular weight ranging 30 from about 200 to 600 are most preferred.

Yet another preferred type of non-aqueous solvent comprises lowermolecular weight methyl esters. Such materials are those of the generalformula: R¹—C(O)—OCH₃ wherein R¹ ranges from 1 to about 18. Examples ofsuitable lower molecular weight methyl esters include methyl acetate,methyl propionate, methyl octanoate, and methyl dodecanoate.

The non-aqueous organic solvent(s) employed should, of course, becompatible and non-reactive with other composition components, e.g.,enzymes, used in the detergent tablets herein. Such a solvent componentwill generally be utilized in an amount of from about 10% to 60% byweight of the gelatinous portion. More preferably, the non-aqueous,low-polarity organic solvent will comprise from about 20% to 50% byweight of the gelatinous portion, most preferably from about 30% to 50%by weight of the gelatinous portion.

b) Gellino Additive

As noted earlier, a gelling agent or additive is added to the nonaqueous solvent of the present invention to complete the thickeningsystem. To form the gel required for suitable phase stability andacceptable rheology of the gelatinous portion, the organic gelling agentis generally present to the extent of a ratio of solvent to gellingagent in thickening system typically ranging from about 99:1 to about1:1. More preferably, the ratios range from about 19:1 to about 4: 1.

The preferred gelling agents of the present invention are selected fromcastor oil derivatives, polyethylene glycol, sorbitols and relatedorganic thixatropes, organoclays, cellulose and cellulose derivatives,pluronics, stearates and stearate derivatives, sugar/gelatincombination, starches, glycerol and derivatives thereof, organic acidamides such as N-lauryl-L-glutamic acid di-n-butyl amide, polyvinylpyrrolidone and mixtures thereof.

The preferred gelling agents include castor oil derivatives. Castor oilis a naturally occurring triglyceride obtained from the seeds of RicinusCommunis, a plant which grows in most tropical or subtropical areas. Theprimary fatty acid moiety in the castor oil triglyceride is ricinoleicacid (12-hydroxy oleic acid). It accounts for about 90% of the fattyacid moieties. The balance consists of dihydroxystearic, palmitic,stearic, oleic, linoleic, linolenic and eicosanoic moieties.Hydrogenation of the oil (e.g., by hydrogen under pressure) converts thedouble bonds in the fatty acid moieties to single bonds, thus“hardening” the oil. The hydroxyl groups are unaffected by thisreaction.

The resulting hydrogenated castor oil, therefore, has an average ofabout three hydroxyl groups per molecule. It is believed that thepresence of these hydroxyl groups accounts in large part for theoutstanding structuring properties which are imparted to the gelatinousportion compared to similar liquid detergent compositions which do notcontain castor oil with hydroxyl groups in their fatty acid chains. Foruse in the compositions of the present invention the castor oil shouldbe hydrogenated to an iodine value of less than about 20, and preferablyless than about 10. Iodine value is a measure of the degree ofunsaturation of the oil and is measured by the “Wijis Method,” which iswell-known in the art. Unhydrogenated castor oil has an iodine value offrom about 80 to 90.

Hydrogenated castor oil is a commercially available commodity beingsold, for example, in various grades under the trademark CASTORWAX.RTM.by NL Industries, Inc., Highstown, N.J. Other Suitable hydrogenatedcastor oil derivatives are Thixcin R, Thixcin E, Thixatrol ST, Perchem Rand Perchem ST, made by Rheox, Laporte. Especially preferred isThixatrol ST.

Polyethylene glycols when employed as gelling agents, rather thansolvents, have a molecular weight range of from about 2000 to about30000, preferably about 4000 to about 12000, more preferably about 6000to about 10000.

Cellulose and cellulose derivatives when employed in the presentinvention preferably include: i) Cellulose acetate and Cellulose acetatephthalate (CAP); ii) Hydroxypropyl Methyl Cellulose (HPMC);iii)Carboxymethylcellulose (CMC); and mixtures thereof. Thehydroxypropyl methylcellulose polymer preferably has a number averagemolecular weight of about 50,000 to 125,000 and a viscosity of a 2 wt. %aqueous solution at 25° C. (ADTMD2363) of about 50,000 to about 100,000cps. An especially preferred hydroxypropyl cellulose polymer isMethocel® J75MS-N wherein a 2.0 wt. % aqueous solution at 25° C. has aviscosity of about 75,000 cps.

The sugar may be any monosaccharide (e.g. glucose), disaccharide (e.g.sucrose or maltose) or polysaccharide. The most preferred sugar iscommonly available sucrose. For the purposes of the present inventiontype A or B gelatin may be used, available from for example Sigma. TypeA gelatin is preferred since it has greater stability in alkalineconditions in comparison to type B. Preferred gelatin also has a bloomstrength of between 65 and 300, most preferably between 75 and 100.

The gelatinous portion of the present invention may include a variety ofother ingredients in addition to the thickening agent as herein beforedescribed and the detergent active disclosed in more detail below.Ingredients such as perfumes and dyes may be included as well asstructure modifying agents. Structure modifying agents include variouspolymers and mixtures of polymers included polycarboxylates,carboxymethylcellulose and starches to aid in adsorption of excesssolvent and/or reduce or prevent “bleeding” or leaking of the solventfrom the gelatinous portion, reduce shrinkage or cracking of thegelatinous portion or aid in the dissolution or breakup of thegelatinous portion in the wash. In addition, hardness modifying agentsmay incorporated into the thickening system to adjust the hardness ofthe gel if desired. These hardness control agents are typically selectedfrom various polymers, such as polyethylene glycol's, polyethyleneoxide, polyvinylpyrrolidone, polyvinyl alcohol, hydroxystearic acid andpolyacetic acid and when included are typically employed in levels ofless than about 20% and more preferably less than about 10% by weight ofthe solvent in the thickening system. For example, hardening agents,such as high molecular weight PEG, preferably of a molecular weight from10,000 to 30,000 or possibly even higher molecular weight, can be addedto decrease the hardening time of the gelatinous portion.

The gelatinous mixture of the present invention is formulated so thatthe gelatinous mixture is a pumpable, flowable mixture at slightlyelevated temperatures of around 30° C. or greater to facilitate deliveryof this mixture into the mold using conventional dosing systems, butbecomes highly viscous or hardens at ambient temperatures so that thegel is maintained in position in the at least one mold in the tabletbody of the detergent tablet through shipping and handling of thedetergent tablet. Such hardening of the gelatinous portion may achieved,for example, by (i) cooling to below the flowable temperature of thegel; (ii) by the removal of shear; (iii) by solvent transfer, forexample either to the atmosphere or to the tablet body; or (iv) bypolymerisation of the gelling agent. Preferably, the gelatinous mixtureis formulated such that the gelatinous portion hardens sufficiently sothat the maximum force needed to push a probe into the dimple preferablyranges from about 0.5N to about 40N. This force may be characterised bymeasuring the maximum force needed to push a probe, fitted with a straingauge, a set distance into the gel. The set distance may be between 40and 80% of the total gel depth. This force can be measured on a QTS 25tester, using a probe of 5 mm diameter. Typical forces measured are inthe range of 1IN to 25N.

The gelatinous mixture may additionally contain a drying agent. Any,conventional drying agent may be employed. See Vogels Text book ofPractical Organic Chemistry, 5^(th) Edition (1989) Longman Scientific &Technical, pp. 165-168, incorporated herein by reference. For example,suitable drying agents are anhydrous CaSO₄, anhydrous Na₂SO₄, sodiumsulfite, calcium chloride and MgSO₄. The selection of suitable dryingagents may depend on the end use of the tablet. A drying agent for adetergent tablet for an automatic dishwashing composition for lowtemperatures preferably is sodium sulfite, or calcium chloride, butanhydrous CaSO₄, may be used for higher use temperatures. When present,drying agents are included in an amount of about 0.1% to about 15%, morepreferably from about 0.1% to about 10%, even more preferably from about0.5% to about 7%, by weight. It is preferred that the drying agent isselected such that it's de-hydration temperature exceeds the processtemperature.

Detergent Actives

Both the gelatinous portion and the tablet body of the present inventiondetergent tablet include at least one detergent active. The gelatinousportion typically contains detergent actives such as surfactants,enzymes, bleaching agents, effervescing agents, silver care agents,builders and the like. The compressed portion typically containsdetergent actives such as builders, surfactants, silicates, pH controlagents or buffers, enzymes and bleaching agents. The following is adescription of the detergent actives useful in the present invention.

Surfactants

Detersive surfactants included in the fully-formulated detergentcompositions afforded by the present invention comprises at least 0.01%,preferably from about 0.5% to about 50%, by weight of detergentcomposition depending upon the particular surfactants used and thedesired effects. In a highly preferred embodiment, the detersivesurfactant comprises from about 0.5% to about 20% by weight of thecomposition.

The detersive surfactant can be nonionic, anionic, ampholytic,zwitterionic, or cationic. Mixtures of these surfactants can also beused. Preferred detergent compositions comprise anionic detersivesurfactants or mixtures of anionic surfactants with other surfactants,especially nonionic surfactants.

Nonlimiting examples of surfactants useful herein include theconventional C₁₁-C₁₈ alkyl benzene sulfonates and primary, secondary andrandom alkyl sulfates, the C₁₀-C₁₈ alkyl alkoxy sulfates, the C₁₈-C₁₈alkyl polyglycosides and their corresponding sulfated polyglycosides,C₁₂-C₁₈ alpha-sulfonated fatty acid esters, C₁₂-C₁₈ alkyl and alkylphenol alkoxylates (especially ethoxylates and mixed ethoxy/propoxy),C₁₂-C₁₈ betaines and sulfobetaines (“sultaines”), C₁₀-C₁₈ amine oxides,and the like. Other conventional useful surfactants are listed instandard texts.

Particularly preferred surfactants in the preferred automaticdishwashing compositions (ADD) of the present invention are low foamingnonionic surfactants (LFNI). LFNI may be present in amounts from 0.01%to about 10% by weight, preferably from about 0.1% to about 10%, andmost preferably from about 0.25% to about 4%. LFNIs are most typicallyused in ADDs on account of the improved water-sheeting action(especially from glass) which they confer to the ADD product. They alsoencompass non-silicone, nonphosphate polymeric materials furtherillustrated hereinafter which are known to defoam food soils encounteredin automatic dishwashing.

Preferred LFNIs include nonionic alkoxylated surfactants, especiallyethoxylates derived from primary alcohols, and blends thereof with moresophisticated surfactants, such as thepolyoxypropylene/polyoxyethylene/polyoxypropylene (PO/EO/PO) reverseblock polymers. The PO/EO/PO polymer-type surfactants are well-known tohave foam suppressing or defoaming action, especially in relation tocommon food soil ingredients such as egg.

The invention encompasses preferred embodiments wherein LFNI is present,and wherein this component is solid at about 95° F. (35° C.), morepreferably solid at about 77° F. (25° C.). For ease of manufacture, apreferred LFNI has a melting point between about 77° F. (25° C.) andabout 140° F. (60° C.), more preferably between about 80° F. (26.6° C.)and 110° F. (43.3° C.).

In a preferred embodiment, the LFNI is an ethoxylated surfactant derivedfrom the reaction of a monohydroxy alcohol or alkylphenol containingfrom about 8 to about 20 carbon atoms, with from about 6 to about 15moles of ethylene oxide per mole of alcohol or alkyl phenol on anaverage basis.

A particularly preferred LFNI is derived from a straight chain fattyalcohol containing from about 16 to about 20 carbon atoms (C₁₆-C₂₀alcohol), preferably a C₁₈ alcohol, condensed with an average of fromabout 6 to about 15 moles, preferably from about 7 to about 12 moles,and most preferably from about 7 to about 9 moles of ethylene oxide permole of alcohol. Preferably the ethoxylated nonionic surfactant soderived has a narrow ethoxylatedistribution relative to the average.

The LFNI can optionally contain propylene oxide in an amount up to about15% by weight. Other preferred LFNI surfactants can be prepared by theprocesses described in U.S. Pat. No. 4,223,163, issued Sep. 16, 1980,Builloty, incorporated herein by reference.

Highly preferred ADDs herein wherein the LFNI is present make use ofethoxylated monohydroxy alcohol or alkyl phenol and additionallycomprise a polyoxyethylene, polyoxypropylene block polymeric compound;the ethoxylated monohydroxy alcohol or alkyl phenol fraction of the LFNIcomprising from about 20% to about 100%, preferably from about 30% toabout 70%, of the total LFNI.

Suitable block polyoxyethylene-polyoxypropylene polymeric compounds thatmeet the requirements described hereinbefore include those based onethylene glycol, propylene glycol, glycerol, trimethylolpropane andethylenediamine as initiator reactive hydrogen compound. Polymericcompounds made from a sequential ethoxylation and propoxylation ofinitiator compounds with a single reactive hydrogen atom, such as C₁₂₋₁₈aliphatic alcohols, do not generally provide satisfactory suds controlin the instant ADDs. Certain of the block polymer surfactant compoundsdesignated PLURONIC® and TETRONIC® by the BASF-Wyandotte Corp.,Wyandotte, Mich. are suitable in ADD compositions of the invention.

A particularly preferred LFNI contains from about 40% to about 70% of apolyoxypropylene/polyoxyethylene/polyoxypropylene block polymer blendcomprising about 75%, by weight of the blend, of a reverse blockco-polymer of polyoxyethylene and polyoxypropylene containing 17 molesof ethylene oxide and 44 moles of propylene oxide; and about 25%, byweight of the blend, of a block copolymer of polyoxyethylene andpolyoxypropylene initiated with trimethylolpropane and containing 99moles of propylene oxide and 24 moles of ethylene oxide per mole oftrimethylolpropane.

Suitable for use as LFNI in the ADD compositions are those LFNI havingrelatively low cloud points and high hydrophilic-lipophilic balance(HLB). Cloud points of 1% solutions in water are typically below about32° C. and preferably lower, e.g., 0° C., for optimum control of sudsingthroughout a full range of water temperatures.

LFNIs which may also be used include those POLY-TERGENT® SLF-18 nonionicsurfactants from Olin Corp., and any biodegradable LFNI having themelting point properties discussed hereinabove.

These and other nonionic surfactants are well known in the art, beingdescribed in more detail in Kirk Othmer's Encyclopedia of ChemicalTechnology, 3rd Ed., Vol. 22, pp. 360-379, “Surfactants and DetersiveSystems”, incorporated by reference herein.

Preferred are ADD compositions comprising mixed surfactants wherein thesudsing (absent any silicone suds controlling agent) is less than 2inches, preferably less than 1 inch, as determined by the disclosurebelow.

The equipment useful for these measurements are: a Whirlpool Dishwasher(model 900) equipped with clear plexiglass door, IBM computer datacollection with Labview and Excel Software, proximity sensor (NewarkCorp.—model 95F5203) using SCXI interface, and a plastic ruler.

The data is collected as follows. The proximity sensor is affixed to thebottom dishwasher rack on a metal bracket. The sensor faces downwardtoward the rotating dishwasher arm on the bottom of the machine(distance approximately 2 cm. from the rotating arm). Each pass of therotating arm is measured by the proximity sensor and recorded. Thepulses recorded by the computer are converted to rotations per minute(RPM) of the bottom arm by counting pulses over a 30 second interval.The rate of the arm rotation is directly proportional to the amount ofsuds in the machine and in the dishwasher pump (i.e., the more sudsproduced, the slower the arm rotation).

The plastic ruler is clipped to the bottom rack of the dishwasher andextends to the floor of the machine. At the end of the wash cycle, theheight of the suds is measured using the plastic ruler (viewed throughthe clear door) and recorded as suds height.

The following procedure is followed for evaluating ADD compositions forsuds production as well as for evaluating nonionic surfactants forutility. (For separate evaluation of nonionic surfactant, a base ADDformula, such as Cascade powder, is used along with the nonionicsurfactants which are added separately in glass vials to the dishwashingmachine.)

First, the machine is filled with water (adjust water for appropriatetemperature and hardness) and proceed through a rinse cycle. The RPM ismonitored throughout the cycle (approximately 2 min.) without any ADDproduct (or surfactants) being added (a quality control check to ensurethe machine is functioning properly). As the machine begins to fill forthe wash cycle, the water is again adjusted for temperature andhardness, and then the ADD product is added to the bottom of the machine(in the case of separately evaluated surfactants, the ADD base formulais first added to the bottom of the machine then the surfactants areadded by placing the surfactant-containing glass vials inverted on thetop rack of the machine). The RPM is then monitored throughout the washcycle. At the end of the wash cycle, the suds height is recorded usingthe plastic ruler. The machine is again filled with water (adjust waterfor appropriate temperature and hardness) and runs through another rinsecycle. The RPM is monitored throughout this cycle.

An average RPM is calculated for the 1st rinse, main wash, and finalrinse. The % RPM efficiency is then calculated by dividing the averageRPM for the test surfactants into the average RPM for the control system(base ADD formulation without the nonionic surfactant). The RPMefficiency and suds height measurements are used to dimension theoverall suds profile of the surfactant.

Also suitable are the so called “end capped” nonionic surfactants. Formore details on these and other suitable nonionic surfactants see U.S.patent Ser. Nos. 60/054,702 (Docket No. 6781P), 60/054,688 (Docket No.6779P) and 60/057,025 (Docket No. 6780P) all of which are incorporatedherein by reference.

Another type of suitable surfactant are the mid-chain branchedsurfactant, such as the mid chain branched alkyl alkoxylates, theso-called “sasol” and the so-called “shell” mid chain branchedsurfactants. For more details on these and other suitable surfactantssee U.S. patent Ser. Nos. 60/061,971 (Docket No. 6881P) filed Oct. 14,1997, 60/061,975 (Docket No. 6882P) filed Oct. 14, 1997, 60/062,086(Docket No. 6883P) filed Oct. 14, 1997, 60/061,916 (Docket No. 6884P)filed Oct. 14, 1997, 60/061,970 (Docket No. 6885P) filed Oct. 14, 1997,60/062,407 (Docket No. 6886P) filed Oct. 14, 1997, 60/031,845 (DocketNo. 6402P), 60/031,916 (Docket No. 6403P) and 60/031,917 (Docket No.6404) all of which are incorporated herein by reference.

Detergent Builders

The present invention may include an optional builder in the productcomposition. The level of detergent salt/builder can vary widelydepending upon the end use of the composition and its desired physicalform. When present, the compositions will typically comprise at leastabout 1% detergent builder and more typically from about 10% to about80%, even more typically from about 15% to about 50% by weight, of thedetergent builder. Lower or higher levels, however, are not meant to beexcluded.

Inorganic or P-containing detergent builders include, but are notlimited to, the alkali metal, ammonium and alkanolammonium salts ofpolyphosphates (exemplified by the tripolyphosphates, pyrophosphates,and glassy polymeric meta-phosphates), phosphonates, phytic acid,silicates, carbonates (including bicarbonates and sesquicarbonates),sulphates, and aluminosilicates. However, non-phosphate salts arerequired in some locales. Importantly, the compositions herein functionsurprisingly well even in the presence of the so-called “weak” builders(as compared with phosphates) such as citrate, or in the so-called“underbuilt” situation that may occur with zeolite or layered silicatebuilders.

Examples of silicate builders are the alkali metal silicates,particularly those having a SiO₂:Na₂O ratio in the range 1.6:1 to 3.2:1and layered silicates, such as the layered sodium silicates described inU.S. Pat. No. 4,664,839, issued May 12, 1987 to H. P. Rieck. NaSKS-6 isthe trademark for a crystalline layered silicate marketed by Hoechst(commonly abbreviated herein as “SKS-6”). Unlike zeolite builders, theNa SKS-6 silicate builder does not contain aluminum. NaSKS-6 has thedelta-Na₂SiO₅ morphology form of layered silicate. It can be prepared bymethods such as those described in German DE-A-3,417,649 andDE-A-3,742,043. SKS-6 is a highly preferred layered silicate for useherein, but other such layered silicates, such as those having thegeneral formula NaMSi_(x)O_(2x+1).yH₂O wherein M is sodium or hydrogen,x is a number from 1.9 to 4, preferably 2, and y is a number from 0 to20, preferably 0 can be used herein. Various other layered silicatesfrom Hoechst include NaSKS-5, NaSKS-7 and NaSKS-1 1, as the alpha, betaand gamma forms. As noted above, the delta-Na₂SiO₅ (NaSKS-6 form) ismost preferred for use herein. Other silicates may also be useful suchas for example magnesium silicate, which can serve as a crispening agentin granular formulations, as a stabilizing agent for oxygen bleaches,and as a component of suds control systems.

Examples of carbonate salts as builders are the alkaline earth andalkali metal carbonates as disclosed in German Patent Application No.2,321,001 published on Nov. 15, 1973.

Aluminosilicate builders may also be added to the present invention as adetergent salt. Aluminosilicate builders are of great importance in mostcurrently marketed heavy duty granular detergent compositions.Aluminosilicate builders include those having the empirical formula:

M_(z)(zAlO₂)_(y) ].xH₂O

wherein z and y are integers of at least 6, the molar ratio of z to y isin the range from 1.0 to about 0.5, and x is an integer from about 15 toabout 264.

Useful aluminosilicate ion exchange materials are commerciallyavailable. These aluminosilicates can be crystalline or amorphous instructure and can be naturally-occurring aluminosilicates orsynthetically derived. A method for producing aluminosilicate ionexchange materials is disclosed in U.S. Pat. No. 3,985,669, Krummel, etal, issued Oct. 12, 1976. Preferred synthetic crystallinealuminosilicate ion exchange materials useful herein are available underthe designations Zeolite A, Zeolite P (B), Zeolite MAP and Zeolite X. Inan especially preferred embodiment, the crystalline aluminosilicate ionexchange material has the formula:

Na₁₂[(AlO₂)₁₂(SiO₂)₁₂ ].xH₂O

wherein x is from about 20 to about 30, especially about 27. Thismaterial is known as Zeolite A. Dehydrated zeolites (x=0-10) may also beused herein. Preferably, the aluminosilicate has a particle size ofabout 0.1-10 microns in diameter.

Organic detergent builders suitable for the purposes of the presentinvention include, but are not restricted to, a wide variety ofpolycarboxylate compounds. As used herein, “polycarboxylate” refers tocompounds having a plurality of carboxylate groups, preferably at least3 carboxylates. Polycarboxylate builder can generally be added to thecomposition in acid form, but can also be added in the form of aneutralized salt. When utilized in salt form, alkali metals, such assodium, potassium, and lithium, or alkanolammonium salts are preferred.

Included among the polycarboxylate builders are a variety of categoriesof useful materials. One important category of polycarboxylate buildersencompasses the ether polycarboxylates, including oxydisuccinate, asdisclosed in Berg, U.S. Pat. No. 3,128,287, issued Apr. 7, 1964, andLamberti et al, U.S. Pat. No. 3,635,830, issued Jan. 18, 1972. See also“TMS/TDS” builders of U.S. Pat. No. 4,663,071, issued to Bush et al, onMay 5, 1987. Suitable ether polycarboxylates also include cycliccompounds, particularly alicyclic compounds, such as those described inU.S. Pat. Nos. 3,923,679; 3,835,163; 4,158,635; 4,120,874 and 4,102,903.

Other useful detergency builders include the etherhydroxypolycarboxylates, copolymers of maleic anhydride with ethylene orvinyl methyl ether, 1,3,5-trihydroxy benzene-2,4,6-trisulphonic acid,and carboxymethyloxysuccinic acid, the various alkali metal, ammoniumand substituted ammonium salts of polyacetic acids such asethylenediamine tetraacetic acid and nitrilotriacetic acid, as well aspolycarboxylates such as mellitic acid, succinic acid, oxydisuccinicacid, polymaleic acid, benzene 1,3,5-tricarboxylic acid,carboxymethyloxysuccinic acid, and soluble salts thereof.

Citrate builders, e.g., citric acid and soluble salts thereof(particularly sodium salt), are polycarboxylate builders of particularimportance. Oxydisuccinates are also especially useful in suchcompositions and combinations.

Also suitable in the detergent compositions of the present invention arethe 3,3-dicarboxy-4-oxa-1,6-hexanedioates and the related compoundsdisclosed in U.S. Pat. No. 4,566,984, Bush, issued Jan. 28, 1986. Usefulsuccinic acid builders include the C₅-C₂₀ alkyl and alkenyl succinicacids and salts thereof. A particularly preferred compound of this typeis dodecenylsuccinic acid. Specific examples of succinate buildersinclude: laurylsuccinate, myristylsuccinate, palmitylsuccinate,2-dodecenylsuccinate (preferred), 2-pentadecenylsuccinate, and the like.Laurylsuccinates are the preferred builders of this group, and aredescribed in European Patent Application 86200690.5/0,200,263, publishedNov. 5, 1986.

Other suitable polycarboxylates are disclosed in U.S. Pat. No.4,144,226, Crutchfield et al, issued Mar. 13, 1979 and in U.S. Pat. No.3,308,067, Diehl, issued Mar. 7, 1967. See also Diehl U.S. Pat. No.3,723,322.

Fatty acids, e.g., C₁₂-C₁₈ monocarboxylic acids, can also beincorporated into the compositions alone, or in combination with theaforesaid builders, especially citrate and/or the succinate builders, toprovide additional builder activity. Such use of fatty acids willgenerally result in a diminution of sudsing, which should be taken intoaccount by the formulator.

Bleaching Agents

Bleaching agents according to the present invention may include bothchlorine and oxygen bleaching systems. Hydrogen peroxide sources aredescribed in detail in the herein incorporated Kirk Othmer'sEncyclopedia of Chemical Technology, 4th Ed (1992, John Wiley & Sons),Vol. 4, pp. 271-300 “Bleaching Agents (Survey)”, and include the variousforms of sodium perborate and sodium percarbonate, including variouscoated and modified forms. An “effective amount” of a source of hydrogenperoxide is any amount capable of measurably improving stain removal(especially of tea stains) from soiled dishware compared to a hydrogenperoxide source-free composition when the soiled dishware is washed bythe consumer in a domestic automatic dishwasher in the presence ofalkali.

More generally a source of hydrogen peroxide herein is any convenientcompound or mixture which under consumer use conditions provides aneffective amount of hydrogen peroxide. Levels may vary widely and areusually in the range from about 0.1% to about 70%, more typically fromabout 0.5% to about 30%, by weight of the compositions herein.

The preferred source of hydrogen peroxide used herein can be anyconvenient source, including hydrogen peroxide itself. For example,perborate, e.g., sodium perborate (any hydrate but preferably the mono-or tetra-hydrate), sodium carbonate peroxyhydrate or equivalentpercarbonate salts, sodium pyrophosphate peroxyhydrate, ureaperoxyhydrate, or sodium peroxide can be used herein. Also useful aresources of available oxygen such as persulfate bleach (e.g., OXONE,manufactured by DuPont). Sodium perborate monohydrate and sodiumpercarbonate are particularly preferred. Mixtures of any convenienthydrogen peroxide sources can also be used.

A preferred percarbonate bleach comprises dry particles having anaverage particle size in the range from about 500 micrometers to about1,000 micrometers, not more than about 10% by weight of said particlesbeing smaller than about 200 micrometers and not more than about 10% byweight of said particles being larger than about 1,250 micrometers.Optionally, the percarbonate can be coated with a silicate, borate orwater-soluble surfactants. Percarbonate is available from variouscommercial sources such as FMC, Solvay and Tokai Denka.

While not preferred for compositions of the present invention whichcomprise detersive enzymes, the present invention compositions may alsocomprise as the bleaching agent a chlorine-type bleaching material. Suchagents are well known in the art, and include for example sodiumdichloroisocyanuratc (“NaDCC”).

(a) Bleach Activators

Preferably, the peroxygen bleach component in the composition isformulated with an activator (peracid precursor). The activator ispresent at levels of from about 0.01% to about 15%, preferably fromabout 0.5% to about 10%, more preferably from about 1% to about 8%, byweight of the composition. Preferred activators are selected from thegroup consisting of tetraacetyl ethylene diamine (TAED),benzoylcaprolactam (BzCL), 4-nitrobenzoylcaprolactam,3-chlorobenzoyl-caprolactam, benzoyloxybenzenesulphonate (BOBS),nonanoyloxybenzene-sulphonate (NOBS), phenyl benzoate (PhBz),decanoyloxybenzenesulphonate (C₁₀-OBS), benzoylvalerolactam (BZVL),octanoyloxybenzenesulphonate (C₈-OBS), perhydrolyzable esters andmixtures thereof, most preferably benzoylcaprolactam andbenzoylvalerolactain. Particularly preferred bleach activators in the pHrange from about 8 to about 9.5 are those selected having an OBS or VLleaving group.

Preferred bleach activators are those described in U.S. Pat. No.5,130,045, Mitchell et al, and 4,412,934, Chung et al, and copendingpatent applications U.S. Ser. Nos. 08/064,624, 08/064,623, 08/064,621,08/064,562, 08/064,564, 08/082,270 and copending application to M. Bums,A. D. Willey, R. T. Hartshorn, C. K. Ghosh, entitled “BleachingCompounds Comprising Peroxyacid Activators Used With Enzymes” and havingU.S. Ser. No. 08/133,691 (P&G Case 4890R), all of which are incorporatedherein by reference.

The mole ratio of peroxygen bleaching compound (as AvO) to bleachactivator in the present invention generally ranges from at least 1:1,preferably from about 20:1 to about 1:1, more preferably from about 10:1to about 3:1.

Quaternary substituted bleach activators may also be included. Thepresent detergent compositions preferably comprise a quaternarysubstituted bleach activator (QSBA) or a quaternary substituted peracid(QSP); more preferably, the former. Preferred QSBA structures arefurther described in U.S. Pat. Nos. 5,460,747, 5,584,888 and 5,578,136,incorporated herein by reference.

(b) Organic Peroxides, especially Diacyl Peroxides

These are extensively illustrated in Kirk Othmer, Encyclopedia ofChemical Technology, Vol. 17, John Wiley and Sons, 1982 at pages 27-90and especially at pages 63-72, all incorporated herein by reference. Ifa diacyl peroxide is used, it will preferably be one which exertsminimal adverse impact on spotting/filming. Preferred is dibenzoylperoxide.

(c) Metal-containing Bleach Catalysts

The present invention compositions and methods utilize metal-containingbleach catalysts that are effective for use in ADD compositions.Preferred are manganese and cobalt-containing bleach catalysts.

One type of metal-containing bleach catalyst is a catalyst systemcomprising a transition metal cation of defined bleach catalyticactivity, such as copper, iron, titanium, ruthenium tungsten,molybdenum, or manganese cations, an auxiliary metal cation havinglittle or no bleach catalytic activity, such as zinc or aluminumcations, and a sequestrate having defined stability constants for thecatalytic and auxiliary metal cations, particularlyethylenediaminetetraacetic acid, ethylenediaminetetra(methylenephosphonic acid) and water-soluble salts thereof. Suchcatalysts are disclosed in U.S. Pat. No. 4,430,243.

Other types of bleach catalysts include the manganese-based complexesdisclosed in U.S. Pat. No. 5,246,621 and U.S. Pat. No. 5,244,594.Preferred examples of theses catalysts include Mn^(IV)₂(u-O)₃(1,4,7-trimethyl-1,4,7-triazacyclononane)₂-(PF₆)₂ (“MnTACN”),Mn^(III)₂(u-O)₁(u-OAC)₂(1,4,7-trimethyl-1,4,7-triazacyclononane)₂-(ClO₄)₂,Mn^(IV) ₄(u-O)₆(1,4,7-triazacyclononane)₄-(ClO₄)₂, Mn^(III)Mn^(IV) ₄^(u-O)) ₁(u-OAc)₂(1,4,7-trimethyl- 1,4,7-triazacyclononane)2-(ClO₄)3,and mixtures thereof. See also European patent application publicationno. 549,272. Other ligands suitable for use herein include1,5,9-trimethyl-1,5,9-triazacyclododecane,2-methyl-1,4,7-triazacyclononane, 2-methyl-1,4,7-triazacyclononane, andmixtures thereof.

The bleach catalysts useful in automatic dishwashing compositions andconcentrated powder detergent compositions may also be selected asappropriate for the present invention. For examples of suitable bleachcatalysts see U.S. Pat. No. 4,246,612 and U.S. Pat. No. 5,227,084.

Other bleach catalysts are described, for example, in European patentapplication, publication no. 408,131 (cobalt complex catalysts),European patent applications, publication nos. 384,503, and 306,089(metallo-porphyrin catalysts), U.S. Pat. No. 4,728,455(manganese/multidentate ligand catalyst), U.S. Pat. No. 4,711,748 andEuropean patent application, publication no. 224,952, (absorbedmanganese on aluminosilicate catalyst), U.S. Pat. No. 4,601,845(aluminosilicate support with manganese and zinc or magnesium salt),U.S. Pat. No. 4,626,373 (manganese/ligand catalyst), U.S. Pat No.4,119,557 (ferric complex catalyst), German Pat. specification 2,054,019(cobalt chelant catalyst) Canadian 866,191 (transition metal-containingsalts), U.S. Pat. No. 4,430,243 (chelants with manganese cations andnon-catalytic metal cations), and U.S. Pat. No. 4,728,455 (manganesegluconate catalysts).

Preferred are cobalt catalysts which have the formula:

[CO(NH₃)_(n)(M′)_(m)]Y_(y)

wherein n is an integer from 3 to 5 (preferably 4 or 5; most preferably5); M′ is a labile coordinating moiety, preferably selected from thegroup consisting of chlorine, bromine, hydroxide, water, and (when m isgreater than 1) combinations thereof; m is an integer from 1 to 3(preferably 1 or 2; most preferably 1); m+n=6; and Y is an appropriatelyselected counteranion present in a number y, which is an integer from 1to 3 (preferably 2 to 3; most preferably 2 when Y is a −1 chargedanion), to obtain a charge-balanced salt.

The preferred cobalt catalyst of this type useful herein are cobaltpentaamine chloride salts having the formula [Co(NH₃)₅Cl]Y_(y), andespecially [Co(NH₃)₅Cl]Cl₂.

More preferred are the present invention compositions which utilizecobalt (III) bleach catalysts having the formula:

[Co(NH3)_(n)(M)_(m)(B)_(b)]T_(y)

wherein cobalt is in the +3 oxidation state; n is 4 or 5 (preferably 5);M is one or more ligands coordinated to the cobalt by one site; m is 0,1 or 2 (preferably 1); B is a ligand coordinated to the cobalt by twosites; b is 0 or 1 (preferably 0), and when b=0, then m+n=6, and whenb=l, then m=0 and n=4; and T is one or more appropriately selectedcounteranions present in a number y, where y is an integer to obtain acharge-balanced salt (preferably y is 1 to 3; most preferably 2 when Tis a−1 charged anion); and wherein further said catalyst has a basehydrolysis rate constant of less than 0.23 M⁻¹ s⁻¹ (25° C.).

Preferred T are selected from the group consisting of chloride, iodide,I₃ ⁻, formate, nitrate, nitrite, sulfate, sulfite, citrate, acetate,carbonate, bromide, PF₆ ⁻, BF₄ ⁻, B(Ph)₄ ⁻, phosphate, phosphite,silicate, tosylate, methanesulfonate, and combinations thereof.Optionally, T can be protonated if more than one anionic group exists inT, e.g., HPO₄ ²⁻, HCO₃ ⁻, H₂PO₄ ⁻, etc. Further, T may be selected fromthe group consisting of non-traditional inorganic anions such as anionicsurfactants (e.g., linear alkylbenzene sulfonates (LAS), alkyl sulfates(AS), alkylethoxysulfonates (AES), etc.) and/or anionic polymers (e.g.,polyacrylates, polymethacrylates, etc.).

The M moieties include, but are not limited to, for example, F⁻, SO₄ ⁻²,NCS⁻, SCN³¹ , S₂O₃ ⁻², NH₃, PO₄ ³⁻, and carboxylates (which preferablyare mono-carboxylates, but more than one carboxylate may be present inthe moiety as long as the binding to the cobalt is by only onecarboxylate per moiety, in which case the other carboxylate in the Mmoiety may be protonated or in its salt form). Optionally, M can beprotonated if more than one anionic group exists in M (e.g., HPO₄ ²⁻,HCO₃ ⁻, H₂PO₄ ⁻, HOC(O)CH₂C(O)O—, etc.) Preferred M moieties aresubstituted and unsubstituted C₁-C₃₀ carboxylic acids having theformulas:

RC(O)O—

wherein R is preferably selected from the group consisting of hydrogenand C₁-C₃₀ (preferably C₁-C₁₈) unsubstituted and substituted alkyl,C₆-C₃₀ (preferably C₆-C₁₈) unsubstituted and substituted aryl, andC₃-C₃₀ (preferably C₅-C₁₈) unsubstituted and substituted heteroaryl,wherein substituents are selected from the group consisting of —NR′₃,—NR′₄ ⁺, —C(O)OR′, —OR′, —C(O)NR′₂, wherein R′ is selected from thegroup consisting of hydrogen and C₁-C₆ moieties. Such substituted Rtherefore include the moieties —(CH₂)_(n)OH and —(CH₂)_(n)NR′₄ ⁺,wherein n is an integer from 1 to about 16, preferably from about 2 toabout 10, and most preferably from about 2 to about 5.

Most preferred M are carboxylic acids having the formula above wherein Ris selected from the group consisting of hydrogen, methyl, ethyl,propyl, straight or branched C₄-C₁₂ alkyl, and benzyl. Most preferred Ris methyl. Preferred carboxylic acid M moieties include formic, benzoic,octanoic, nonanoic, decanoic, dodecanoic, malonic, maleic, succinic,adipic, phthalic, 2-ethylhexanoic, naphthenoic, oleic, palmitic,triflate, tartrate, stearic, butyric, citric, acrylic, aspartic,fumaric, lauric, linoleic, lactic, malic, and especially acetic acid.

The B moieties include carbonate, di- and higher carboxylates (e.g.,oxalate, malonate, malic, succinate, maleate), picolinic acid, and alphaand beta amino acids (e.g., glycine, alanine, beta-alanine,phenylalanine).

Cobalt bleach catalysts useful herein are known, being described forexample along with their base hydrolysis rates, in M. L. Tobe, “BaseHydrolysis of Transition-Metal Complexes”, Adv. Inorg. Bioinorz. Mech.,(1983), 2, pages 1-94. For example, Table 1 at page 17, provides thebase hydrolysis rates (designated therein as k_(OH)) for cobaltpentaamine catalysts complexed with oxalate (k_(OH)=2.5×10⁻⁴ M⁻¹ s⁻¹(25° C.)), NCS⁻ (k_(OH)=5.0×10⁻⁴ M⁻¹ s⁻¹ (25° C.)), formate(k_(OH)=5.8×10⁻⁴ M⁻¹ s⁻¹ (25° C.)), and acetate (k_(OH)=9.6×10⁻⁴ M⁻¹ s⁻¹(25° C.)). The most preferred cobalt catalyst useful herein are cobaltpentaamine acetate salts having the formula [Co(NH₃)₅OAc]Ty, wherein OAcrepresents an acetate moiety, and especially cobalt pentaamine acetatechloride, [Co(NH₃)₅OAc]Cl₂; as well as [Co(NH₃)₅OAc](OAc)₂;[Co(NH₃)₅OAc](PF₆)₂; [Co(NH₃)₅OAc](SO₄); [Co(NH₃)₅OAc](BF₄)₂; and[Co(NH₃)₅OAc](NO₃)₂.

Cobalt catalysts according to the present invention made be producedaccording to the synthetic routes disclosed in U.S. Pat. Nos. 5,559,261,5,581,005, and 5,597,936, the disclosures of which are hereinincorporated by reference.

These catalysts may be co-processed with adjunct materials so as toreduce the color impact if desired for the aesthetics of the product, orto be included in enzyme-containing particles as exemplifiedhereinafter, or the compositions may be manufactured to contain catalyst“speckles”.

As a practical matter, and not by way of limitation, the cleaningcompositions and cleaning processes herein can be adjusted to provide onthe order of at least one part per hundred million of the active bleachcatalyst species in the aqueous washing medium, and will preferablyprovide from about 0.01 ppm to about 25 ppm, more preferably from about0.05 ppm to about 10 ppm, and most preferably from about 0.1 ppm toabout 5 ppm, of the bleach catalyst species in the wash liquor. In orderto obtain such levels in the wash liquor of an automatic dishwashingprocess, typical automatic dishwashing compositions herein will comprisefrom about 0.0005% to about 0.2%, more preferably from about 0.004% toabout 0.08%, of bleach catalyst by weight of the cleaning compositions.

Detersive Enzymes

The compositions of the present invention may also include the presenceof at least one detersive enzyme. “Detersive enzyme”, as used herein,means any enzyme having a cleaning, stain removing or otherwisebeneficial effect in a composition. Preferred detersive enzymes arehydrolases such as proteases, amylases and lipases. Highly preferred forautomatic dishwashing are amylases and/or proteases, including bothcurrent commercially available types and improved types which, thoughmore bleach compatible, have a remaining degree of bleach deactivationsusceptibility.

In general, as noted, preferred compositions herein comprise one or moredetersive enzymes. If only one enzyme is used, it is preferably anamyloytic enzyme when the composition is for automatic dishwashing use.Highly preferred for automatic dishwashing is a mixture of proteolyticenzymes and amyloytic enzymes. More generally, the enzymes to beincorporated include proteases, amylases, lipases, cellulases, andperoxidases, as well as mixtures thereof. In particular, mixtures of twoor more protease enzymes and/or two or more amylase enzymes arepreferred. Other types of enzymes may also be included. They may be ofany suitable origin, such as vegetable, animal, bacterial, fungal andyeast origin. However, their choice is governed by several factors suchas pH-activity and/or stability optima, thermostability, stabilityversus active detergents, builders, etc. In this respect bacterial orfungal enzymes are preferred, such as bacterial amylases and proteases,and fungal cellulases.

Enzymes are normally incorporated in the instant detergent compositionsat levels sufficient to provide a “cleaning-effective amount”. The term“cleaning-effective amount” refers to any amount capable of producing acleaning, stain removal or soil removal effect on substrates such asfabrics, dishware and the like. Since enzymes are catalytic materials,such amounts may be very small. In practical terms for currentcommercial preparations, typical amounts are up to about 5 mg by weight,more typically about 0.01 mg to about 3 mg, of active enzyme per gram ofthe composition: Stated otherwise, the compositions herein willtypically comprise from about 0.001% to about 6%, preferably 0.01%-1% byweight of a commercial enzyme preparation. Protease enzymes are usuallypresent in such commercial preparations at levels sufficient to providefrom 0.005 to 0.1 Anson units (AU) of activity per gram of composition.For automatic dishwashing purposes, it may be desirable to increase theactive enzyme content of the commercial preparations, in order tominimize the total amount of non-catalytically active materialsdelivered and thereby improve spotting/filming results.

Suitable examples of proteases are the subtilisins which are obtainedfrom particular strains of B. subtilis and B. licheniformis. Anothersuitable protease is obtained from a strain of Bacillus, having maximumactivity throughout the pH range of 8-12, developed and sold by NovoIndustries A/S as ESPERASE®. The preparation of this enzyme andanalogous enzymes is described in British Patent Specification No.1,243,784 of Novo. Proteolytic enzymes suitable for removingprotein-based stains that are commercially available include those soldunder the tradenames ALCALASE®, DURAZYM® and SAVINASE® from Novo andMAXATASE®, MAXACAL®, PROPERASE®, PURAFECT® and MAXAPEM® (proteinengineered Maxacal) from Genencor. Other proteases include Protease A(see European Patent Application 130,756, published Jan. 9, 1985) andProtease B (see European Patent Application Serial No. 87303761.8, filedApr. 28, 1987, and European Patent Application 130,756, Bott et al,published Jan. 9, 1985).

An especially preferred protease, referred to as “Protease D” is acarbonyl hydrolase variant having an amino acid sequence not found innature, which is derived from a precursor carbonyl hydrolase bysubstituting a different amino acid for a plurality of amino acidresidues at a position in said carbonyl hydrolase equivalent to position+76, preferably also in combination with one or more amino acid residuepositions equivalent to those selected from the group consisting of +99,+101, +103, +104, +107, +123, +27, +105, +109, +126, +128, +135, +156,+166, +195, +197, +204, +206, +210, +216, +217, +218, +222, +260, +265,and/or +274 according to the numbering of Bacillus amyloliquefacienssubtilisin, as described in WO 95/10615 published Apr. 20, 1995 byGenencor International, and U.S. Pat. Nos. 5,677,272 and 5,679,630.

Other preferred protease enzymes include protease enzymes which are acarbonyl hydrolase variant having an amino acid sequence not found innature, which is derived by replacement of a plurality of amino acidresidues of a precursor carbonyl hydrolase with different amino acids,wherein said plurality of amino acid residues replaced in the precursorenzyme correspond to position +210 in combination with one or more ofthe following residues: +33, +62, +67, +76, +100, +101, +103, +104,+107, +128, +129, +130, +132, +135, +156, +158, +164, +166, +167, +170,+209, +215, +217, +218 and +222, where the numbered positions correspondto naturally-occurring subtilisin from Bacillus amyloliquefaciens or toequivalent amino acid residues in other carbonyl hydrolases orsubtilisins (such as Bacillus lentus subtilisin). Preferred enzymesaccording include those having position changes +210, +76, +103, +104,+156, and +166.

Useful proteases are also described in PCT publications: WO 95/30010published Nov. 9, 1995 by The Procter & Gamble Company; WO 95/30011published Nov. 9, 1995 by The Procter & Gamble Company; WO 95/29979published Nov. 9, 1995 by The Procter & Gamble Company.

Amylases suitable herein include, for example, α-amylases described inBritish Patent Specification No. 1,296,839 (Novo), RAPIDASE®,International Bio-Synthetics, Inc. and TERMAMYL®, Novo Industries,Purafect Ox Am® from Genencor and Ban®, Fungamyl® and Duramyl®,

Preferred amylases herein have the commonalty of being derived usingsite-directed mutagenesis from one or more of the Baccillus amylases,especially the Bacillus alpha-amylases, regardless of whether one, twoor multiple amylase strains are the immediate precursors.

As noted, “oxidative stability-enhanced” amylases are preferred for useherein despite the fact that the invention makes them “optional butpreferred” materials rather than essential. Such amylases arenon-limitingly illustrated by the following:

(a) An amylase according to the hereinbefore incorporated WO/94/02597,Novo Nordisk A/S, published Feb. 3, 1994, as further illustrated by amutant in which substitution is made, using alanine or threonine(preferably threonine), of the methionine residue located in position197 of the B. licheniformis alpha-amylase, known as TERMAMYL®, or thehomologous position variation of a similar parent amylase, such as B.amyloliquefaciens, B. subtilis, or B. stearothermophilus;

(b) Stability-enhanced amylases as described by Genencor Internationalin a paper entitled “Oxidatively Resistant alpha-Amylases” presented atthe 207th American Chemical Society National Meeting, Mar. 13-17 1994,by C. Mitchinson. Therein it was noted that bleaches in automaticdishwashing detergents inactivate alpha-amylases but that improvedoxidative stability amylases have been made by Genencor from B.licheniformis NCIB8061. Methionine (Met) was identified as the mostlikely residue to be modified. Met was substituted, one at a time, inpositions 8,15,197,256,304,366 and 438 leading to specific mutants,particularly important being M197L and M197T with the M197T variantbeing the most stable expressed variant. Stability was measured inCASCADE® and SUNLIGHT®;

(c) Particularly preferred are amylase variants as disclosed inWO95/26397 and in the co-pending application to Novo NordiskPCT/IDK96/00056 and characterized by having a specific activity at least25% higher than the specific activity of Termamyl® at a temperaturerange of 25° C. to 55° C. and at a pH value in the range of 8 to 10,measured by the Phadebas® α-amylase activity assay and is obtained froman alkalophilic Bacillus species (such as the strains NCIB 12289, NCIB12512, NCIB 12513 and DSM 935) comprising the following amino acidsequence in the N-terminal:His-His-Asn-Gly-Thr-Asn-Gly-Thr-Met-Met-Gln-Tyr-Phe-Glu-Trp-Tyr-Leu-Pro-Asn-Asp.

Cellulases usable in, but not preferred, for the present inventioninclude both bacterial or fungal cellulases. Typically, they will have apH optimum of between 5 and 9.5. Suitable cellulases are disclosed inU.S. Pat. No. 4,435,307, Barbesgoard et al, issued Mar. 6, 1984. whichdiscloses fungal cellulase produced from Humicola insolens and Humicolastrain DSM1800 or a cellulase 212-producing fungus belonging to thegenus Aeromonas, and cellulase extracted from the hepatopancreas of amarine mollusk (Dolabella Auricula Solander). Suitable cellulases arealso disclosed in GB-A-2.075.028; GB-A-2.095.275 and DE-OS-2.247.832.CAREZYME® (Novo) is especially useful.

Suitable lipase enzymes for detergent use include those produced bymicroorganisms of the Pseudomonas group, such as Pseudomonas stutzeriATCC 19.154, as disclosed in British Patent 1,372,034. See also lipasesin Japanese Patent Application 53,20487, laid open to public inspectionon Feb. 24, 1978. This lipase is available from Amano Pharmaceutical Co.Ltd., Nagoya, Japan, under the trade name Lipase P “Amano,” hereinafterreferred to as “Amano-P.” Other commercial lipases include Amano-CES,lipases ex Chromobacter viscosum, e.g. Chromobacter viscosum var.lipolyticum NRRLB 3673, commercially available from Toyo Jozo Co.,Tagata, Japan; and further Chromobacter viscosum lipases from U.S.Biochemical Corp., U.S.A. and Disoynth Co., The Netherlands, and lipasesex Pseudomonas gladioli. The LIPOLASE® enzyme derived from Humicolalanuginosa and commercially available from Novo (see also EPO 341,947)is a preferred lipase for use herein. Another preferred lipase enzyme isthe D96L variant of the native Humicola lanuginosa lipase, as describedin WO 92/05249 and Research Disclosure No. 35944, Mar. 10, 1994, bothpublished by Novo. In general, lipolytic enzymes are less preferred thanamylases and/or proteases for automatic dishwashing embodiments of thepresent invention.

Peroxidase enzymes can be used in combination with oxygen sources, e.g.,percarbonate, perborate, persulfate, hydrogen peroxide, etc. They aretypically used for “solution bleaching,” i.e. to prevent transfer ofdyes or pigments removed from substrates during wash operations to othersubstrates in the wash solution. Peroxidase enzymes are known in theart, and include, for example, horseradish peroxidase, ligninase, andhaloperoxidase such as chloro- and bromo-peroxidase.Peroxidase-containing detergent compositions are disclosed, for example,in PCT International Application WO 89/099813, published Oct. 19, 1989,by O. Kirk, assigned to Novo Industries A/S. The present inventionencompasses peroxidase-free automatic dishwashing compositionembodiments.

A wide range of enzyme materials and means for their incorporation intosynthetic detergent compositions are also disclosed in U.S. Pat. No.3,553,139, issued Jan. 5, 1971 to McCarty et al. Enzymes are furtherdisclosed in U.S. Pat. No. 4,101,457, Place et al, issued Jul. 18, 1978,and in U.S. Pat. No. 4,507,219, Hughes, issued Mar. 26, 1985. Enzymesfor use in detergents can be stabilized by various techniques. Enzymestabilization techniques are disclosed and exemplified in U.S. Pat. No.3,600,319, issued Aug. 17, 1971 to Gedge, et al, and European PatentApplication Publication No. 0 199 405, Application No. 86200586.5,published Oct. 29, 1986, Venegas. Enzyme stabilization systems are alsodescribed, for example, in U.S. Pat. No. 3,519,570.

Disruptino Agents

The detergent tablet of the present invention may further comprise adisrupting agent. Disrupting agents are typically included in the tabletat levels of from about 5% to about 60% and more preferably from about20% to about 50%. The disrupting agent may be a disintegrating oreffervescing agent. Preferably, the disrupting agents of the presentinvention will be included in the gelatinous portion. Suitabledisintegrating agents include agents that swell on contact with water orfacilitated water influx and/or efflux by forming channels in compressedand/or non-compressed portions. Any known disintegrating or effervescingagent suitable for use in laundry or dishwashing applications isenvisaged for use herein. Suitable disintegrating agent include starch,starch derivatives, alginates, carboxymethylcellulose (CMC), CMC-basedpolymers, sodium acetate, aluminium oxide. Other optional disruptingaids include organic and inorganic acids such as maleic acid, malicacid, hydrochloric acid, sodium hydroxide and layered silicates.Suitable effervescing agents are those that produce a gas on contactwith water. Suitable effervescing agents may be oxygen, nitrogen dioxideor carbon dioxide evolving species. Examples of preferred effervescingagents may be selected from the group consisting of perborate,percarbonate, carbonate, bicarbonate and carboxylic acids such as citricor maleic acid.

pH and Buffering Variation

Many detergent compositions herein will be buffered, i.e., they arerelatively resistant to pH drop in the presence of acidic soils.However, other compositions herein may have exceptionally low bufferingcapacity, or may be substantially unbuffered. Techniques for controllingor varying pH at recommended usage levels more generally include the useof not only buffers, but also additional alkalis, acids, pH-jumpsystems, dual compartment containers, etc., and are well known to thoseskilled in the art.

The preferred compositions herein comprise a pH-adjusting componentselected from water-soluble alkaline inorganic salts and water-solubleorganic or inorganic builders. The pH-adjusting components are selectedso that when the composition is dissolved in water at a concentration of1,000-10,000 ppm, the pH remains in the range of above about 6,preferably from about 9.5 to about 11.5. In fact, included in thepresent invention, is a detergent tablet wherein varying pH can beachieved in the wash process. For instance, the gelatinous portion ofthe tablet may rapidly dissolve adjusting the pH to one level, forexample, neutral to slightly basic or about 6.0 to about 8.0, followedby slower dissolution of the tablet body raising the pH to from about9.5 to about 11.5 wherein the pH of the composition is altered toprovide improved cleaning performance. The preferred nonphosphatepH-adjusting component of the invention is selected from the groupconsisting of:

(i) sodium carbonate or sesquicarbonate;

(ii) sodium silicate, preferably hydrous sodium silicate havingSiO₂:Na₂O ratio of from about 1:1 to about 2:1, and mixtures thereofwith limited quantities of sodium metasilicate;

(iii) sodium citrate;

(iv) citric acid;

(v) sodium bicarbonate;

(vi) sodium borate, preferably borax;

(vii) sodium hydroxide; and

(viii) mixtures of (i)-(vii).

Preferred embodiments contain low levels of silicate (i.e. from about 3%to about 10% SiO₂).

The amount of the pH adjusting component in the instant composition ispreferably from about 1% to about 50%, by weight of the composition. Ina preferred embodiment, the pH-adjusting component is present in thecomposition in an amount from about 5% to about 40%, preferably fromabout 10% to about 30%, by weight.

Water-Soluble Silicates

The present compositions may further comprise water-soluble silicates.Water-soluble silicates herein are any silicates which are soluble tothe extent that they do not adversely affect spotting/filmingcharacteristics of the ADD composition.

Examples of silicates are sodium metasilicate and, more generally, thealkali metal silicates, particularly those having a SiO₂:Na₂O ratio inthe range 1.6:1 to 3.2:1; and layered silicates, such as the layeredsodium silicates described in U.S. Pat. No. 4,664,839, issued May 12,1987 to H. P. Rieck. NaSKS-6® is a crystalline layered silicate marketedby Hoechst (commonly abbreviated herein as “SKS-6”). Unlike zeolitebuilders, Na SKS-6 and other water-soluble silicates useful herein donot contain aluminum. NaSKS-6 is the δ-Na₂SiO₅ form of layered silicateand can be prepared by methods such as those described in GermanDE-A-3,417,649 and DE-A-3,742,043. SKS-6 is a preferred layered silicatefor use herein, but other such layered silicates, such as those havingthe general formula NaMSi_(x)O_(2x+1).yH₂O wherein M is sodium orhydrogen, x is a number from 1.9 to 4, preferably 2, and y is a numberfrom 0 to 20, preferably 0 can be used. Various other layered silicatesfrom Hoechst include NaSKS-5, NaSKS-7 and NaSKS-11, as the α-, β- andγ-forms. Other silicates may also be useful, such as for examplemagnesium silicate, which can serve as a crispening agent in granularformulations, as a stabilizing agent for oxygen bleaches, and as acomponent of suds control systems.

Silicates particularly useful in automatic dishwashing (ADD)applications include granular hydrous 2-ratio silicates such asBRITESIL® H20 from PQ Corp., and the commonly sourced BRITESIL® H24though liquid grades of various silicates can be used when the ADDcomposition has liquid form. Within safe limits, sodium metasilicate orsodium hydroxide alone or in combination with other silicates may beused in an ADD context to boost wash pH to a desired level.

Chelating Agents

The compositions herein may also optionally contain one or moretransition-metal selective sequestrants, “chelants” or “chelatingagents”, e.g., iron and/or copper and/or manganese chelating agents.Chelating agents suitable for use herein can be selected from the groupconsisting of aminocarboxylates, phosphonates (especially theaminophosphonates), polyfunctionally-substituted aromatic chelatingagents, and mixtures thereof. Without intending to be bound by theory,it is believed that the benefit of these materials is due in part totheir exceptional ability to control iron, copper and manganese inwashing solutions which are known to decompose hydrogen peroxide and/orbleach activators; other benefits include inorganic film prevention orscale inhibition. Commercial chelating agents for use herein include theDEQUEST® series, and chelants from Monsanto, DuPont, and Nalco, Inc.

Aminocarboxylates useful as optional chelating agents are furtherillustrated by ethylenediaminetetracetates,N-hydroxyethylethylenediaminetriacetates, nitrilotriacetates,ethylenediamine tetraproprionates, triethylenetetraaminehexacetates,diethylenetriamine-pentaacetates, and ethanoldiglycines, alkali metal,ammonium, and substituted ammonium salts thereof. In general, chelantmixtures may be used for a combination of functions, such as multipletransition-metal control, long-term product stabilization, and/orcontrol of precipitated transition metal oxides and/or hydroxides.

Polyfunctionally-substituted aromatic chelating agents are also usefulin the compositions herein. See U.S. Pat. No. 3,812,044, issued May 21,1974, to Connor et al. Preferred compounds of this type in acid form aredihydroxydisulfobenzenes such as 1,2-dihydroxy-3,5-disulfobenzene.

A highly preferred biodegradable chelator for use herein isethylenediamine disuccinate (“EDDS”), especially (but not limited to)the [S,S] isomer as described in U.S. Pat. No. 4,704,233, Nov. 3, 1987,to Hartman and Perkins. The trisodium salt is preferred though otherforms, such as magnesium salts, may also be useful.

Aminophosphonates are also suitable for use as chelating agents in thecompositions of the invention when at least low levels of totalphosphorus are acceptable in detergent compositions, and include theethylenediaminetetrakis (methylenephosphonates) and thediethylenetriaminepentakis (methylene phosphonates). Preferably, theseaminophosphonates do not contain alkyl or alkenyl groups with more thanabout 6 carbon atoms.

If utilized, chelating agents or transition-metal-selective sequestrantswill preferably comprise from about 0.001% to about 10%, more preferablyfrom about 0.05% to about 1% by weight of the compositions herein.

Organic Polymeric Compound

Organic polymeric compounds may be added as preferred components of thedetergent tablets in accord with the invention. By organic polymericcompound it is meant essentially any polymeric organic compound commonlyfound in detergent compositions having dispersant, anti-redeposition,soil release agents or other detergency properties.

Organic polymeric compound is typically incorporated in the detergentcompositions of the invention at a level of from 0.1% to 30%, preferablyfrom 0.5% to 15%, most preferably from 1% to 10% by weight of thecompositions.

Examples of organic polymeric compounds include the water solubleorganic homo- or co-polymeric polycarboxylic acids, modifiedpolycarboxylates or their salts in which the polycarboxylic acidcomprises at least two carboxyl radicals separated from each other bynot more than two carbon atoms. Polymers of the latter type aredisclosed in GB-A-1,596,756. Examples of such salts are polyacrylates ofmolecular weight 2000-10000 and their copolymers with any suitable othermonomer units including modified acrylic, fumaric, maleic, itaconic,aconitic, mesaconic, citraconic and methylenemalonic acid or theirsalts, maleic anhydride, acrylamide, alkylene, vinylmethyl ether,styrene and any mixtures thereof. Preferred are the copolymers ofacrylic acid and maleic anhydride having a molecular weight of from20,000 to 100,000.

Preferred commercially available acrylic acid containing polymers havinga molecular weight below 15,000 include those sold under the tradenameSokalan PA30, PA20, PA15, PA10 and Sokalan CP10 by BASF GmbH, and thosesold under the tradename Acusol 45N, 480N, 460N by Rohm and Haas.

Preferred acrylic acid containing copolymers include those which containas monomer units: a) from 90% to 10%, preferably from 80% to 20% byweight acrylic acid or its salts and b) from 10% to 90%, preferably from20% to 80% by weight of a substituted acrylic monomer or its saltshaving the general formula -[CR₂-CR₁(CO—O—R₃)]- wherein at least one ofthe substituents R₁, R₂ or R₃, preferably R₁ or R₂ is a 1 to 4 carbonalkyl or hydroxyalkyl group, R₁ or R₂ can be a hydrogen and R₃ can be ahydrogen or alkali metal salt. Most preferred is a substituted acrylicmonomer wherein R₁ is methyl, R₂ is hydrogen (i.e. a methacrylic acidmonomer). The most preferred copolymer of this type has a molecularweight of 3500 and contains 60% to 80% by weight of acrylic acid and 40%to 20% by weight of methacrylic acid.

The polyamine and modified polyamine compounds are useful hereinincluding those derived from aspartic acid such as those disclosed inEP-A-305282, EP-A-305283 and EP-A-351629.

Other optional polymers may polyvinyl alcohols and acetates bothmodified and non-modified, cellulosics and modified cellulosics,polyoxyethylenes, polyoxypropylenes, and copolymers thereof, bothmodified and non-modified, terephthalate esters of ethylene or propyleneglycol or mixtures thereof with polyoxyalkylene units.

Suitable examples are disclosed in U.S. Pat. Nos. 5,591,703, 5,597,789and 4,490,271.

Material Care Agents

The present compositions may contain one or more material care agentswhich are effective as corrosion inhibitors and/or anti-tarnish aids.Such materials are preferred components of machine dishwashingcompositions especially in certain European countries where the use ofelectroplated nickel silver and sterling silver is still comparativelycommon in domestic flatware, or when aluminum protection is a concernand the composition is low in silicate. Generally, such material careagents include metasilicate, silicate, bismuth salts, manganese salts,paraffin, triazoles, pyrazoles, thiols, mercaptans, aluminum fatty acidsalts, and mixtures thereof.

When present, such protecting materials are preferably incorporated atlow levels, e.g., from about 0.01% to about 5% of the ADD composition.Suitable corrosion inhibitors include paraffin oil, typically apredominantly branched aliphatic hydrocarbon having a number of carbonatoms in the range of from about 20 to about 50; preferred paraffin oilis selected from predominantly branched C₂₅₋₄₅ species with a ratio ofcyclic to noncyclic hydrocarbons of about 32:68. A paraffin oil meetingthose characteristics is sold by Wintershall, Salzbergen, Germany, underthe trade name WINOG 70. Additionally, the addition of low levels ofbismuth nitrate (i.e., Bi(NO₃)₃) is also preferred.

Other corrosion inhibitor compounds include benzotriazole and comparablecompounds; mercaptans or thiols including thionaphtol and thioanthranol;and finely divided Aluminum fatty acid salts, such as aluminumtristearate. The formulator will recognize that such materials willgenerally be used judiciously and in limited quantities so as to avoidany tendency to produce spots or films on glassware or to compromise thebleaching action of the compositions. For this reason, mercaptananti-tarnishes which are quite strongly bleach-reactive and common fattycarboxylic acids which precipitate with calcium in particular arepreferably avoided.

Silicone and Phosphate Ester Suds Supnressors

The compositions of the invention can optionally contain an alkylphosphate ester suds suppressor, a silicone suds suppressor, orcombinations thereof. Levels in general are from 0% to about 10%,preferably, from about 0.001% to about 5%. However, generally (for costconsiderations and/or deposition) preferred compositions herein do notcomprise suds suppressors or comprise suds suppressors only at lowlevels, e.g., less than about 0.1% of active suds suppressing agent.

Silicone suds suppressor technology and other defoaming agents usefulherein are extensively documented in “Defoaming, Theory and IndustrialApplications”, Ed., P. R. Garrett, Marcel Dekker, N.Y., 1973, ISBN0-8247-8770-6, incorporated herein by reference. See especially thechapters entitled “Foam control in Detergent Products” (Ferch et al) and“Surfactant Antifoams” (Blease et al). See also U.S. Pat. Nos. 3,933,672and 4,136,045. Highly preferred silicone suds suppressors are thecompounded types known for use in laundry detergents such as heavy-dutygranules, although types hitherto used only in heavy-duty liquiddetergents may also be incorporated in the instant compositions. Forexample, polydimethylsiloxanes having trimethylsilyl or alternateendblocking units may be used as the silicone. These may be compoundedwith silica and/or with surface-active nonsilicon components, asillustrated by a suds suppressor comprising 12% silicone/silica, 18%stearyl alcohol and 70% starch in granular form. A suitable commercialsource of the silicone active compounds is Dow Corning Corp.

If it is desired to use a phosphate ester, suitable compounds aredisclosed in U.S. Pat. No. 3,314,891, issued Apr. 18, 1967, to Schmolkaet al, incorporated herein by reference. Preferred alkyl phosphateesters contain from 16-20 carbon atoms. Highly preferred alkyl phosphateesters are monostearyl acid phosphate or monooleyl acid phosphate, orsalts thereof, particularly alkali metal salts, or mixtures thereof.

It has been found preferable to avoid the use of simplecalcium-precipitating soaps as antifoams in the present compositions asthey tend to deposit on the dishware. Indeed, phosphate esters are notentirely free of such problems and the formulator will Generally chooseto minimize the content of potentially depositing antifoams in theinstant compositions.

Adiunct Materials

Detersive ingredients or adjuncts optionally included in the instantcompositions can include one or more materials for assisting orenhancing cleaning performance, treatment of the substrate to becleaned, or designed to improve the aesthetics of the compositions.Adjuncts which can also be included in compositions of the presentinvention, at their conventional art-established levels for use(generally, adjunct materials comprise, in total, from about 30% toabout 99.9%, preferably from about 70% to about 95%, by weight of thecompositions), include other active ingredients such as non-phosphatebuilders, chelants, enzymes, suds suppressors, dispersant polymers(e.g., from BASF Corp. or Rohm & Haas), color speckles, silvercare,anti-tarnish and/or anti-corrosion agents, silicates, dyes, fillers,germicides, alkalinity sources, hydrotropes, anti-oxidants, enzymestabilizing agents, perfumes, solubilizing agents, carriers, processingaids, pigments, and pH control agents.

Depending on whether a greater or lesser degree of compactness isrequired, filler materials can also be present in the instantcompositions. These include sucrose, sucrose esters, sodium sulfate,potassium sulfate, etc., in amounts up to about 70%, preferably from 0%to about 40% of the composition. Preferred filler is sodium sulfate,especially in good grades having at most low levels of trace impurities.

Sodium sulfate used herein preferably has a purity sufficient to ensureit is non-reactive with bleach; it may also be treated with low levelsof sequestrants, such as phosphonates or EDDS in magnesium-salt form.Note that preferences, in terms of purity sufficient to avoiddecomposing bleach, applies also to pH-adjusting component ingredients,specifically including any silicates used herein.

Hydrotrope materials such as sodium benzene sulfonate, sodium toluenesulfonate, sodium cumene sulfonate, etc., can be present, e.g., forbetter dispersing surfactant.

Bleach-stable perfumes (stable as to odor); and bleach-stable dyes suchas those disclosed in U.S. Pat. No. 4,714,562, Roselle et al, issuedDecember 22, 1987 can also be added to the present compositions inappropriate amounts.

Since the compositions herein can contain water-sensitive ingredients oringredients which can co-react when brought together in an aqueousenvironment, it is desirable to keep the free moisture content at aminimum, e.g., 7% or less, preferably 5% or less of the compositions;and to provide packaging which is substantially impermeable to water andcarbon dioxide. Coating measures have been described herein toillustrate a way to protect the ingredients from each other and from airand moisture. Plastic bottles, including refillable or recyclable types,as well as conventional barrier cartons or boxes are another helpfulmeans of assuring maximum shelf-storage stability. As noted, wheningredients are not highly compatible, it may further be desirable tocoat at least one such ingredient with a low-foaming nonionic surfactantfor protection. There are numerous waxy materials which can readily beused to form suitable coated particles of any such otherwiseincompatible components; however, the formulator prefers those materialswhich do not have a marked tendency to deposit or form films on dishesincluding those of plastic construction.

Process

The detergent tablets of the present invention are prepared byseparately preparing the composition of active detergent componentsforming the respective tablet body and the gelatinous portion, formingthe tablet body and delivering the gelatinous mixture to the at leastone mold in the tablet body.

The tablet body is prepared by obtaining the granular detergent mixture.The granular detergent mixture contains at least one active detergentcomponent and optionally premixing with carrier components. Anypre-mixing will be carried out in a suitable mixer; for example a panmixer, rotary drum, vertical blender or high shear mixer or by othersuitable conventional means such as agglomeration. Preferably dryparticulate components are admixed in a mixer, as described above, andliquid components are applied to the dry particulate components, forexample by spraying the liquid components directly onto the dryparticulate components. The resulting mixture is then formed into thetablet body in a compression step using any known suitable equipment.Preferably the tablet body is formed into a tablet body using a tabletpress, wherein the tablet body is prepared by compression of thegranular detergent mixture between an upper and a lower punch. In apreferred embodiment of the present invention the composition isdelivered into a punch cavity, or die, of a tablet press and compressedto form a tablet body using a pressure of preferably greater than 6.3KN/cm², more preferably greater than 9 KN/cm², most preferably greaterthan 10.8 KN/cm².

In order to form a tablet body wherein the first surface has a mold toreceive the gelatinous mixture, the tablet body is prepared using amodified tablet press comprising modified upper and/or lower punches.The upper and lower punches of the modified tablet press are modifiedsuch that the first surface of the tablet body provides one or moreindentations which form the mold(s) to which the gelatinous mixture isdelivered.

Preparation of the Gelatinous Mixture

The gelatinous mixture is prepared in two steps. This can be donebatchwise or continuously. The following describes the batchwisepreparation procedure. It is preferred that the gelatinous mixturecontain a thickening system and a detergent active agent.

Preparation of Thickening System

The preferred preparation of the gelatinous mixture involves the use ofa thickening system. The thickening system preferably comprises a liquiddiluent and a gelling additive. The preferred gelling agent is apolyethylene glycol (PEG), having a molecular weight of from about 3000to 8000. Suitable PEG, such as Pluracol E-6000, are available from BASFor Union Carbide and should be substantially free of water.

If the PEG is in a solid form (e.g. a flake or prill), then it must bemelted by heating, preferably at about 62 C. When the PEG is completelymelted, a dye may optionally be added, such as Sandolin blue dye, slowlyand thoroughly mixed into the molten PEG. This mixture is maintained asa molten mixture at a temperature of about 62 C.

The liquid diluent or solvent is added. The preferred solvent is aglycerol triacetate which is substantially free of water, also know asTriacetin, which is available from Eastman Corporation as Food GradeTriacetin.

The Triacetin is heated and maintained at a temperature of 50 C. Therequired amount of the PEG/dye mixture is added slowly to the Triacetinunder slight agitation. The rate of addition is monitored to assure thePEG is dissolved into the Triacetin. Once addition is completed theTriacetin/PEG pre-mix is cooled to about 48° C. and maintained at thattemperature with low, but continuous agitation This premix has theformula given in Table A and is referred to as Premix “A”.

TABLE A Premix “A” Ingredient Amount (wt. %) Triacetin solvent 90.000Polyethylene glycol (MW = 8000) 9.996 Sandolin blue dye 0.004

Preparation of Gelatinous Mixture

The required amount of Premix A, as shown in Table B, is placed in amixing vessel and maintained at a temperature of about 48° C. withthorough agitation, such as that provided by a Winkworth Contra rotatinganchor blade stirrer. While agitating, the individual solid ingredientsare added successively to Premix A in the order and amounts indicated inTable B. The addition of calcium chloride, citric acid, and sodiumbicarbonate cause the temperature of the mixture to fall to from about40° C. to about 42° C. The temperature is maintained at about 40° C. forthe addition of the enzymes, to prevent and minimize any thermaldegradation of the enzyme.

TABLE B Final Solid/Liquid Mixture Order of Addition Ingredient Wt. % 1Triacetin/PEG/dye mix (Premix A) 40.01 2 Drying agent, such as, Calciumchloride, 5.00 anhydrous 3 Disruption agent, such as, Sodium 19.83bicarbonate, anhydrous 4 Disruption agent, such as, Citric acid, 14.5anhydrous 5 Enzyme, such as, a protease prill 7.83 6 Enzyme, such as, anamylase enzyme prill 12.83

When the mixture is completed it should be held at about 37 C withslight agitation in a covered tank to avoid contamination and anyabsorption of water from the air.

Filling Process

The final mixture can be dosed into the top cavity of the tablets usingany of a number of types of dosing equipment. Filling can be done byvolume, for example using a piston-type volumetric filling head.Alternatively, the filling can be done by weight. One such process,referred to herein as a unit weight dosing process, fills the tabletswhile they are sitting on a scale. The empty tablet is weighed and thescale is tared. The tablet is then filled while sitting on the scale.The flow is cut off when the target dosage amount is obtained.

Another process for filling the tablets is really a variation on theunit weight dosing process described above. In this process a nozzleopens and closes intermittently and the dosed amount is controlled bythe flowrate of the mixture and the open time of the dosing valve. Onesuch system is made and marketed by Cavalla. The tablets are deliveredon a conveyor under a dosing valve. A photocell detects the presence ofthe tablets and signals the opening of the dosing valve and thesimultaneous closing of a shutoff valve on the recirculation side of thevalve. The open time of the valve is controlled by a solenoid and theopen time is either preset based on calibrations or controlled in theprocess based on feedback of dosing weights from a checkweigher orfeed-forward from a mass flowmeter. In either case, the dosed amount iscontrolled by the open time of the nozzle.

It is critical that all equipment be selected to avoid destruction offragile or sensitive components of the mixture, such as enzyme prills.Pumps must be selected which can handle a high solids content withoutdamage to the individual solid particles. Gear pumps and other pumpswith tight clearances between intermeshing gears or rotor/statorcomponents can cause unacceptable shearing of the solid particles.Particularly preferred pumps are progressive cavity pumps, such as Moyno(made by Robbins and Meyers in North America) which are well known fortheir ability to pump solid/liquid suspensions accurately withoutdamaging the physical integrity of the solid particles. Other pumpswhich can meter particles in the 50-1000 micron size range without sizereduction or damage to the solid particles may also be employed.

In this process, the piping of the process is critical. It is best tominimize the amount of piping to avoid settling of the solids from themixture. It is also critical to keep the mixture moving at all times.Practically this is accomplished by use of the recirculation loop and abypass loop which allow the mixture to be flowing at all times. This isa critical process requirement and is independent of the type of dosingequipment employed.

In addition, with proper control of the temperature (which controls therheological properties of the mixture), very accurate dosing can beachieved independent of whether the dosing is done by volume, by time orby weight. For the indicated formula, the mixture should be controlledat a temperature of 37+/−3° C. to maintain the self-leveling propertiesof the mixture and to deliver a consistent viscosity to the dosingnozzle. Practically this is accomplished byjacketing the tank and allpiping. The dosing nozzle can also be heated by placing the valve withinan electrically heated metal block.

Conveyor speeds can be chosen based on the size of the tablet to befilled, the optimum dosing time, and the desired orientation of thetablets. Maximum rates can be obtained by spacing the tablets as closeas possible while leaving enough of a gap between tablets to allowreliable resetting of the valve between successive fillings.Practically, the minimum gap between tablets is about 0.125 inchesalthough use of more advanced detection techniques could allow this toreduce even further. Higher rates can be obtained by filling the tabletswhile they are moving in a direction perpendicular to their longestside. Under these conditions, it is possible to dose up to 100 tabletsper minute from a single dosing nozzle.

The nozzle size must be determined to achieve best possible filling ofthe tablets and to avoid blockage by the solids in the mixture. Althougha variety of shapes can be employed, the orifice is preferably roundwith a diameter from about 0.125 inches to about 0.5 inches, morepreferably between about 0.25 and about 0.375 inches.

The nozzle should be placed as close as possible to the tablet cavity inorder to avoid splashing which can be caused when the impact velocity istoo high. Preferably the nozzle orifice will be located between about0.125 and about 0.5 inches, more preferably about 0.25 inches from thetop plane of the tablet.

While the formulation disclosed above is self-leveling, formulationswhich are not self-leveling can still be used successfully. Leveling canbe achieved by tapping or vibrating the tablets immediately afterfilling. This can be accomplished mechanically or using othertechnologies for inducing vibration for example using ultrasonics.

The subject formulation hardens to the point of being non-flowing withinabout 5 minutes. The hardening time can be substantially reduced byaccelerating the rate of cooling of the gel after filling. This can beaccomplished in a number of ways, including but not limited to use of acooling tunnel, pre-cooling the empty tablet bodies, or a combination ofthese approaches. The hardening rate can also be increased through useof a higher molecular weight PEG, typically a PEG with a molecularweight of about 20,000 or higher, in the formulation.

The detergent tablets may be employed in any conventional domesticwashing process wherein detergent tablets are commonly employed,including but not limited to automatic dishwashing and fabriclaundering.

The following non limiting examples further illustrate the presentinvention.

Abbreviations used in Examples

In the detergent compositions, the abbreviated component identificationshave the following meanings:

STPP : Sodium tripolyphosphate Citrate : Tri-sodium citrate dihydrateBicarbonate : Sodium hydrogen carbonate Citric Acid : Anhydrous Citricacid Carbonate : Anhydrous sodium carbonate Silicate : Amorphous SodiumSilicate (SiO₂:Na₂O ratio = 1.6- 3.2) Metasilicate : Sodium metasilicate(SiO₂:Na₂O ratio = 1.0) PB1 : Anhydrous sodium perborate monohydrate PB4: Sodium perborate tetrahydrate of nominal formula NaBO₂.3H₂O.H₂O₂ TAED: Tetraacetyl ethylene diamine HEDP : Ethane 1-hydroxy-1,1-diphosphonicacid DETPMP : Diethyltriamine penta (methylene) phosphonate, marketed byMonsanto under the tradename Dequest 2060 PAAC : Pentaamine acetatecobalt (III) salt Paraffin : Paraffin oil sold under the tradename Winog70 by Wintershall. Protease : Proteolytic enzyme Amylase : Amylolyticenzyme. BTA : Benzotriazole PA30 : Polyacrylic acid of average molecularweight approximately 4,500 pH : Measured as a 1% solution in distilledwater at 20° C.

EXAMPLE 1

A multi-layer detergent tablet according to the present invention may beprepared as follows. A detergent composition as in Example 3,formulation C is prepared and passed into a conventional rotary press.The press includes one punch shaped so that an indentation is formedinto one of the tablet surfaces. A gelatinous mixture formulation asdisclosed in Example 3, formulation C is then prepared. The properamount of non-aqueous solvent is provided to a mixer and shear isapplied to the solvent at a moderate rate (2,500-5,000 rpm). The properamount of gelling agent is gradually added to the solvent under shearconditions until the mixture is homogeneous. The shear rate of themixture is gradually increased to high shear condition of around 10,000rpm. The temperature of the mixture is increased to between 55° C. and60° C. The shear is then stopped and the mixture is allowed to cool totemperatures between 40° C. and 45° C. Using a low shear mixer, theremaining ingredients are then added to the mixture as solids. The finalmixture is then metered into the indentation on the compressed tabletbody and allowed to cool until the gel hardens or is no longer flowable.

EXAMPLE 2

A multi-layer detergent tablet according to the present invention may beprepared as follows: A detergent composition as in Example 3,formulation A is prepared and passed into a conventional rotary press.The press includes one punch shaped so that an indentation is formedinto one of the tablet surfaces. A gel matrix formulation as disclosedin Example 3, formulation A is then prepared. The proper amount ofnon-aqueous solvent is provided to a mixer where low shear is appliedand the mixture is heated to about 50° C. The proper amount of gellingagent is gradually added to the solvent under stirring until dissolved.The temperature of the mixture or solution is allowed to cool down tobetween 37° C.+/−3° C. However, the temperature of the mixture shouldnot fall below 35° C. at any time during the mixing and dispensing.Using low shear, the remaining ingredients are then added to thesolution as solids.

This mixture is then delivered to the tablets by pumping the mixturecontinuously through a Moyno progressive cavity pump and intermittentlydosing it into the moulds of successive tablets through a valve and anozzle having a {fraction (5/16)}″ round opening. The fluidintermittently switches between exiting the dosing nozzle andrecirculating back to the usage tank. This is controlled by two nozzleswhich operate simultaneously. When the valve opens to the dosing nozzle,the valve to the recirculation line closes. When the valve to the dosingnozzle closes, the valve to the recirculation line opens. A pressureregulating valve on the recirculation line instead of a 2-way pistontype valve will also work.

The nozzle is located about ¼ inch above the top plane of the tabletswhich are traveling on a conveyor passing beneath the dosing nozzle.Successive tablets are located about ¼ inch, although they are notregistered perfectly, nor do they need to be. A photocell detects thepresence of the tablets as they approach the nozzle and signals theopening of the dosing valve and the simultaneous closing of the shutoffvalve on the recirculation line. A programmable controller is used toset the open time of the nozzle, which in this case is about 0.5seconds. The fluid flows into the mold and levels by itself. In thisparticular example, filling is accomplished at a rate of 60tablets/minute.

The tablets are conveyed immediately into a cooling tunnel where theyare cooled and hardened to the point of being non-flowing in about 1minute. The hardening time can be reduced even further by providing morecooling.

EXAMPLE 3

Detergent Tablets according to the present invention may be formulatedas follows:

A B C D E F Tablet Body STPP 52.80 55.10 51.00 — 50.00 38.20 Citrate — —— 26.40 — — Carbonate 15.40 14.00 14.00 — 18.40 15.00 Silicate 12.6014.80 15.00 26.40 10.00 10.10 Protease — 1.00 — — — — Amylase 0.95 0.750.75 0.60 2.0 0.85 PB1 12.60 12.50 12.50 1.56 15.70 11.00 PB4 — — — 6.92— — Nonionic 1.65 1.50 2.00 1.50 0.80 1.65 PAAC — 0.016 — 0.012 — 0.008TAED — — — 4.33 1.30 — HEDP — — — 0.67 — 0.92 DETPMP — — — 0.65 — —Paraffin — 0.50 0.50 0.42 — — BTA — 0.30 0.30 0.24 — — PA30 — — — 3.20 —— Perfume 0.05 — — — 0.20 0.20 Sulphate — — — 24.05 10.68 22.07Misc/water to balance Weight (g) 20.00 20.00 20.50 20.00 30.00Gelatinous portion Savinase ® 12.80 — 10.00 4.50 — 4.00N76D/S103A/V104I¹ — 8.00 — 4.50 8.00 4.00 Termamyl ® 7.20 — 12.00 5.00 —— Amylase² — 13.00 — 5.00 — 13.00 Bicarbonate 24.00 13.00 11.50 13.006.00 Citric acid 18.00 13.00 11.50 14.00 6.00 Dipropyleneglycol — —50.00 40.00 — 35.00 butylether Glycerol Triacetate 34.00 40.00 — — 48.00— Thixatrol ST ® — — 5.00 7.00 4.00 — Polyethylene glycol³ 4.00 2.00 — —— 3.00 Metasilicate — — — 7.00 — 41.00 Silicate — 11.00 — — 28.00 —Weight (g) 3.50 3.00 3.50 3.00 5.00 5.00 ¹As disclosed in U.S. Pat. No.5,677,272. ²Amylase enzyme as disclosed in Novo Nordisk applicationPCT/DK96/00056 and is obtained from an alkalophilic Bacillus specieshaving a N-terminal sequence of:His-His-Asn-Gly-Thr-Asn-Gly-Thr-Met-Met-Gln-Tyr-Phe-Glu-Trp-Tyr-Leu-Pro-Asn-Asp.³MW 4,000-8,000.

What is claimed is:
 1. A process for preparing a multi-phase detergenttablet comprising the steps of: a) forming a tablet body by compressinga granular detergent mixture, said tablet body having a first surface,said first surface having at least one mold therein and said granulardetergent mixture comprising at least one detergent active agent; b)providing a gelatinous mixture under constant agitation, and deliveringsaid gelatinous mixture to said at least one mold in said tablet body toform a gelatinous portion, said gelatinous mixture comprising at leastone detergent active agent and a thickening system comprising a gellingadditive and a liquid diluent wherein the liquid diluent is selectedfrom the group consisting of propylene glycols, alkylene glycol monolower alkyl ethers, ethoxylated or propoxylated ethylene or propylene,glycerol esters, glycerol triacetate, lower molecular weightpolyethylene glycols, lower molecular weight methyl esters and amides,and mixtures thereof; and c) hardening or curing said gelatinous portionto form a multi-phase detergent tablet.
 2. A process for preparing amulti-phase detergent tablet according to claim 1, wherein saidgelatinous mixture is added to said at least one mold in meteredamounts.
 3. A process for preparing a multi-phase detergent tabletaccording to claim 1, wherein said process is a continuous process.
 4. Aprocess for preparing a multi-phase detergent tablet according to claim1, wherein said gelatinous mixture is formed by mixing said thickeningsystem with said at least one detergent active agent.
 5. A process forpreparing a multi-phase detergent tablet according to claim 1, whereinsaid process further comprises the step of cooling said tablet bodyprior to delivery of said gelatinous mixture.
 6. A process for preparinga multi-phase detergent tablet according to claim 1, wherein saidgranular detergent mixture is compressed by a rotary press.
 7. A processfor preparing a multi-phase detergent tablet according to claim 1,wherein said detergent active agents are selected from the groupconsisting of enzymes, bleach system, disrupting system, drying agent,builder, chelant, surfactant, pH adjusting agent and mixtures thereof.8. A process for preparing a multi-phase detergent tablet according toclaim 1, wherein said step of hardening said gelatinous portioncomprises a cooling step.
 9. A process for preparing a multi-phasedetergent tablet according to claim 1, wherein said step of providingsaid gelatinous mixture comprises the steps of first melting saidgelling additive and subsequently adding said liquid diluent to form athickening system premix, placing said premix under agitation and addingsaid detergent active agent to form said gelatinous mixture.
 10. Aprocess for preparing a multi-phase detergent tablet according to claim7, wherein said enzyme is selected from the group consisting ofprotease, amylase, cellulase, lipase, and mixtures thereof.
 11. Aprocess for preparing a multi-phase detergent tablet according to claim1, wherein said gelling additive is selected from the group consistingof polyethylene glycols having a molecular weight from about 2,000 toabout 30,000 castor oil derivatives, sorbitol, cellulose, sugar/gelatincombinations and mixtures thereof.
 12. A process for preparing amulti-phase detergent tablet according to claim 1, wherein said step ofhardening further comprises a step of leveling said gelatinous mixturein said mold before curing of the gel.
 13. A process for preparing amulti-phase detergent tablet according to claim 1, wherein said processfurther comprises the step of delivering said gelatinous portion to saidat least one mold by a progressive cavity pump.
 14. A process forpreparing a multi-phase detergent tablet according to claim 1 whereinsaid gelling additive is melted at a temperature of between about 45° C.to about 75° C.
 15. A process for preparing a multi-phase detergenttablet according to claim 1, wherein the temperature of said gelatinousmixture prior to hardening or curing is from about 30° C. to about 40°C.
 16. A process for preparing a multi-phase detergent tablet accordingto claim 1, wherein said gelling additive is polyethylene glycol.